I need help upgrading my system

Yes, my room does have carpeting. Also, will any of these speakers sound any better than others with metal and gaming from my pc? Also, say I went with the denon amp and the b&w speakers, should I continue to use the sonic maximizer?

Yeah, the deal is that the Cheap Denon's with the new Audyssey EQ is going to be LIGHT YEARS better than anything else you could EQ your system with! So, even if you go 2 channel, you'll still be WAY ahead of the game, sound-wise. Infact, you'll be even better off, as you'll be needing less processing power - because you're using only 2 speakers, not multiples, which need EQ'ing.
For you? I'd be looking at high efficiency, possibly horn driver or multiple mid/bass driver speaker designs! You need something that can be driven by lower powered on a budget, if you're not doing separates.
Again, with something like a $450 Denon (retail - much less on net), you should be looking at Klipsch's, Dappolito's, and dual mid/bass designs, which do better at dynamics. That's for bookshelves, and preferably floorstanders, also. For your room, with the Audyssey, you could EQ out floorstandars. But rock will be better running speakers as "small", and letting a powered sub handle the bass! You'll then be bi-amping your system, while getting an active sub into the mix. In fact, I'd be looking at bookshelves, if it where me, and doing a sub, yes. Better flexibility for best sound, all around, I think. However, with an efficient enough speaker, you could get away with EQing it out, and proper setup, for great reasults, if careful. Some speakers out there offer active woofers, so look around.
My first thought for you, for a budget, with superb sonics for you, is the Cheapest Denon with Audyssey, MultEQ. Then look for either some horn speakers, like Klipsch RB-25's, or some Dappolito designs, like Paradigm, NHT, or PSB L/C/R's used on the net. These will all be dynamic for rock, and help reinforce transient response, while being more room acoustic friendly, wiht added efficiency.
Another very strong option for you to look at, in a more high-end, but affordable speaker option, is to look at the Triangle Titus and Comet speakers! These offer a simple crossover, which makes the speaker respond more like an active speaker! This improve dynamics greatly, as does the horn like tweeter they use. These are WELL worth a try for you!
Sub? I'd look at some 10" you find a good deal on, which has a good bunch of reviews. (I found a killer little 8" sub for $20 on craigslist.com). So look around - same for speakers.
You can then scout around for speaker wire cheap, and IC's, tweaks, etc.
Hope this helps.

Thanks for the help, Flrnlamb. I'm gonna go with the cheapest denon. Do I need one with Audyssey? And if so, which one is the cheapest with it?

What does Dappolito mean?

Any other recomendations with the fact that I'll be listening to metal and gaming w/ them in mind? And also price is a big factor too.

Thanks for the help so far everyone!

~max

Also, I'd rather not have a sub, so what speakers would be efficient, be good with metal and games, have active bass, and be fairly cheap (used)?

Active woofers? Well, years back, Home Theater Magazine did a $3k system face off" between 3 of the writers. The one that won the challenge used some then current Boston Acoustics powered mini tower speakers, which used some 8" active woofers, driven by a Jolida 40watt/ch tube integrated amp!! The same system looped in a simple DD Yamaha AV receiver for movie dubties, and processing DD/DTS sources. This system won because of the excellent mating between the more refined sounding tube amplifier, and the efficient dynamic clear sound of the semi active speakers.
Well I know Definitive Technology made a similar type of speaker that retailed for $500 ea, or $1000/pr, range. They, I believe, were the BP2006tl's. These, while not Dappolito (woofer-over tweeter-over woofer), still offer quite strong dynamics, and a clear, workable sound, similar to the sound of the Bostons - which sound better with tubes. Mated with some little tube integrated amp, you would have an excellent sound, with pretty darn good dynamics for rock! It's a thought. Of course, then were talking no system EQ here - which, in your tiny room, would be a HUGE benefit, indeed.
Since your room is so tiny, you will DEFINITELY need the benefit of the newer Audyssey technology! So, you could jump on one of the Denon AVR-688's or 1708's on ebay for around $285-300 range, and mate them with similar speakers I described. Then, you might even look into finding some innexpensive tube integrated or amp to mate up with em down the line - which you could then loop the Denon into for movies. I think it's a thought.
Other route is to go with some high efficiency Klipsch RF-5's(?), with the same Denon combo - maybe trying the tube amp in the system, down the line.
It's going to be hard to keep a low budget, and still get you full range speakers, room eq, and quality sound! You go with certain combo's, and then you need more amplifier, separates amps, more expensive speakers, and so on...so it's tough.
Actually, your challenge here, for a cheap budget, with great dyanmic sound,and quality overall sound, is the floor standing speakers, sans the sub! I could get better quality in some nice bookshelves, adding a great deal on some little 8" or 10" sub
hope tis heps...