The only difference between home theatre speakers and PC speakers is quality. Obviously the home theatre speakers will be far superior.
Now let me explain what is going on here.
Your speakers are simply mechanisms which change electric signals into kinetic energy which your ears interpret as sound. Your receiver will take a signal (either digital or analog) and increase (amplify) the signal to be used by the speakers. Your soundcard is what actually processes the sound signal, the device that converts the little bit stream in your computer to a signal that an amplification device can use. Using 5.1 sound with EAX is more dependent on your sound card being able to process the signal than anything else. You will just have to make sure your theatre can accept 5.1 signals, or whatever configuration your home theatre is (different configs are 2, 2.1, 4, 4.1, 7.1, etc....). Make sure the sound card matches the theatre's configuration. Your soundcard will have documentation on how to setup the card.
If you want accurate 3d positioning, you will have to make sure your speakers are placed properly as well. This is important no matter what speakers you use.
I use a 2.1 configuration that I sometimes convert over to headphones. It's spectacularely easy to do.
XP 2500+ Barton @ 198x11.5@1.85v
Thermalright SLK-800
Thermaltake Smartfan II
A7N8X Dlx
2x512MB Corsair PC3200
BBA 9700 Pro AIW
2x80GB 7200RPM Maxtor
Soundstorm