Bah...sorry...I'm an idiot. I somehow missed reading the part in your first post where you said that you also have a TV and game console and perhaps a couple of other sources in your office as well
My bad!
With that in mind, I'll just say what I would do in your situation with your budget.
I'd start with a capable receiver. An A/V receiver will act as your "hub", handling the audio from all of your sources (PC, game console, Cable box, etc.) and also handle switching the video between your various sources.
Now, I'm not exactly sure what output options you have from your PC. If your PC has an HDMI output, then things are easy and you can just run the HDMI output from your PC to the receiver and you're all set for both video and audio. Similarly, if you have a digital audio output from your PC - either optical or S/PDIF, you can just run a digital audio connection from your PC to the receiver for the PC's audio. However, if you are using multi-channel analogue outputs from a PC soundcard, then it's a touch more complicated. What you will need are stereo 3.5mm-to-stereo RCA (red/white) cables and multi-channel analogue inputs on your receiver.
So, what I'm going to suggest is a receiver that has ALL of these options so that no matter what your audio output situation is from your PC, you'll be covered
Normally, I prefer Denon receivers, but sadly, Denon has chosen to no longer include multi-channel analogue audio inputs except on their higher-priced receivers. So instead, the receiver I'm going to recommend is the Onkyo TX-NR709. Now, the 709 is technically still a pre-order, though it should start shipping to retailers at the end of April. If you need this new setup right away, then the TX-NR708 is available and it will offer all of the input options that I just mentioned as well. The new 709 is not a large upgarde from the 708, but it does have a couple of nice feature upgrades - including the more robust Audyssey MultEQ XT auto-setup/EQ program vs. the slightly less capable MultEQ offered in the 708. The 709 also has better video processing. Both offer Apple AirPlay - although the 708 requires a firmware update to make that happen while the 709 will have it out of the box. One other cool thing is that the 708 and 709 even offer a VGA input, so if, for some weird reason, you're still using an analogue VGA video output from your PC, or you just want to run a dual monitor DVI+VGA output, the 708/709 can even handle that!
So anywho, that's the receiver I would get. You can pre-order the 709 from B&H Photo (a great retailer) right now for $800 and they'll ship it out as soon as they get their stock from Onkyo. The 708 is on clearance now, so you can find it under $600 if you look around. I'll leave it to you to decide whether you want to pay the little bit extra and also if you're willing to wait for the 709 to ship for the few little upgrades that the 709 offers.
Now, the next thing is going to be a subwoofer. Being an office, I'm going to assume that a smaller size for the subwoofer would be preferable. Myself, I'd go with a compact, sealed subwoofer. But I'd still be looking for deep extension - I just wouldn't be so worried about really loud output.
At the top of my list, just in terms of performance, would be the SVSound SB13-Plus. The 13-Plus driver is an absolute BEAST and I've been extremely impressed with SVSound's new "Sledge" amplifiers. That said, the SB13-Plus might be overkill, both in terms of output capability and in terms of size.
One subwoofer option that really jumps out for an office is the Axiom Audio EP400. It's tiny, but it can dig right down to honest 20Hz output! It won't play loud way down there, but in an office, it's just about perfect! It's very small size is preferable IMO and no other subwoofer at that size can dig down to honest 20Hz output like the little Axiom EP400. Many people baulk at the price tag being over $1000 for such a small sub, but you're paying for a remarkably engineered little 8" driver, a very powerful amp with an analogue power section (very rare at this output level) and some pretty sophisticated DSP processing, which is what allows such a small sub to play so low!
I'd also consider the Rythmik F12. The F12 is bigger than the Axiom EP400, but smaller than the SVSound SB13-Plus. It's the least powerful of all three, but also the least expensive. And when super-loud output is not necessary (which it shouldn't be in an office), it's a great performer in a compact package.
Anywho, those are some subwoofer options. And to be honest, if it were me, I'd probably go with the Axiom, just for the super small size and yet amazing, deep output!
So that's going to burn through somewhere around $2000 of your budget give or take with the subwoofer and receiver. Be absolutely sure to tack on $50 for a decoupling device for your subwoofer! I recommend the Auralex SubDude or the Auralex GRAMMA if the SubDude isn't quite large enough. Decoupling is, IMO, absolutely vital for any subwoofer, so be sure to include that in your purchase and just consider it as part of the cost of your subwoofer!
Now, for speakers, you've got a lot of options.
One of the great things about the Onkyo TX-NR709/708 that I recommended is that it also offers 7.2 pre-outs. That means that you can opt for regular home theater speakers, or you can still opt for self-powered professional studio monitors!
I'm still partial to the Focal Professional monitors for a nearfield setup. If you just want to run a stereo pair, the Solo6Be will still fit your budget. If you want to run 5 speakers, then you'll have to step down to the CMS line in order to stay within budget. The CMS line is also quite a bit physically smaller, so they might make a lot more sense than the rather large Solo6Be anyway. Something like matching CMS 50 all around would be SPECTACULAR in terms of sound quality.
If you don't want to go the self-powered professional monitor route though, I'm going to recommend that you go with the Aperion Audio Verus Grand speakers. Now why, out of all the speakers out there, would I pick these Aperions over everything else? Simple - the tweeter. The new tweeter used in the Verus Grand speakers is something special and is particularly well suited to near-field listening - which is the trait that puts them over the top for me. You can basically put your ear right up against the Verus Grand tweeter and you still won't hear any trace of distortion. It's remarkable, and it's something that most other home speakers just cannot offer. With most home speakers - and even a lot of studio monitors - if you put your ear really close to the tweeter, you'll hear a faint hiss and you might catch some distortion coming through or even have a bit of separation between the treble and mid-range where the tweeter and woofer don't quite blend together without adequate distance from the speaker to the listener. The Verus Grand Bookshelf speakers do not suffer these problems. You can get right up on that tweeter and it will still sound flawless!
The Aperion Verus Grand are certainly within your budget and they are the way I'd go for sure if I didn't go with the self-powered Focal Professional CMS monitors. The great news is, either way, the Onkyo TX-NR709/708 has you covered, so you can decide for yourself without worry!
Hope that helps!
