Need Speaker/Subwoofer Suggestions

Hey guys, I've decided to take my first step into the magical world of audiophiles ( second step if you count me buying a Sennheiser PC360 headset   ) and was wanting to get some advice real quick. I'm on an $600-800 budget so I know I can't get anything close to the great stuff but I'd still like to get the best that I can.

So after a bit of research I'm currently thinking of getting two Mackie MR5MKIIs to replace my current Logitech Z 623 setup and I'm still in need of a nice powered subwoofer ( I don't want to mess with amps if possible ) that compliments the Mackies. I haven't yet decided on a subwoofer and I'm still willing to look into other speakers/monitors if you guys can offer any better alternatives. Basically I'm not wanting to spend more than $400 on the pair of speakers/monitors and I'd rather not spend more than $400 on the sub by itself either.

These will be getting plugged directly into my PC's Creative Sound Blaster X-Fi Titanium Soundcard and I want to make sure that I have the ability to upgrade to 5.1 in the future just in-case it pans out that I find the room to do this later on down the road.

I'll mainly be using them for gaming but I also listen to plenty of music ( mostly light rock and techno if that matters ) and watch the occasional movie.

So what do you guys suggest within that price range for a complete 2.1 setup?

Thank you in advance!

800 bucks total. I was thinking of getting a pair of $400 dollar speakers first then getting a $400 sub for the setup afterwards. But really if it wouldn't make much difference in sound quality I'd like to try to keep around the $600 limit for all three together.

Also does anyone know how the Mackie's compare to the Swan M200MKIIIs? If they are really that much better I might go with them instead.