Hey,
I'm currently using a Logitech PC speaker set Z-3. I listened to some hifi speakers a while ago and decided that I need a new set of speakers!

Anyway, I need help in picking out the best possible set for me.
At the moment, the only thing I think I could use in the setup is my PC as the sound source with my Creative X-Fi Fatal1ty (The one from the original four card line-up, below platinum.). I also got some SPDIF out ports on the front panel and I guess I should use them to output the signal? As I said, I only have the PC so I guess I'm gonna need an amplifier also. Budget would be somewhere around +-500€ but I'm willing to go above it also for something like 100-150€. The speakers should be bookshelf speakers, I think.
I went to a Hi-Fi shop and they recommended me a pair of Q-Acoustics 2020 and a Firestone BigJoe 3 amplifier. What do you think about these? I'm kinda suspicious about that amp since I've never seen an amp that small. That set would cost me 550€. Also, the sales guy said that I shouldn't get a subwoofer since it's not necessary.
So, what speakers and amplifier (or receiver, don't know the difference) should I get? Should I invest in to a subwoofer also?