What size TV are you looking at? This is the time to buy a TV, they are clearing out the 2011s for the 2012 models and there doesn't appear to be any new technology coming out in the 2012s. I'd get the TV now while they are clearing them out. Do you have any stereo equipment at all? The TV's audio out hooked up to a stereo receiver and speakers can be a starting point. Normally I'd say start with a receiver (that "special box with a bunch of rca cable jacks"), and drop your first $600 or so (after the TV) there, but without any speakers, that's a pointless purchase on its own. I'm working with speakers from my old Onkyo HTIB system with towers borrowed from my stereo system. Works well for now until I get my new speakers.
I would personally do something like this:
Assuming you spend more than $1200 on the TV, go to a local bigger store and get the TV. Get it on credit, a lot of places are offering 18-36 months interest free financing right now, and their clearance prices aren't that far off from web retailers.
Now, go get your butt in every retailer you can find and listen to as many speakers as you can while you save up for the audio end of the system. Don't be scared to ask to listen to that pair of $15,000 Martin Logan electrostats, most people who do couldn't afford them, but it gives you a reference. While you are there, if you find a pair of speakers you like, try them out with different receivers, and play around with the receiver's functions and features if you can.
After you find some things you like, narrowed down your choices, made your final pics and hopefully socked away some cash, I'd then get my front right and front left speaker and a full fledged HT Receiver.
Spend the next month or so researching subs. I would personally go internet direct on the sub. After you picked your sub and saved up your cash, go for it. You now have a 2.1 system.
Just three speakers away from a full 5.1 system, now its just the saving game cause you already picked out your speakers and have a functional 2.1 system.
5.1 system done, OK, now you have to decide if you want to stop there or go 7.1, or even 7.2
That's just how I would do it.