Easy. As far as the portability, that's more up to you, but I'll voice my idea.
Speakers:
http://www.bestbuy.com/site/olspage....=1138085354138
Receiver:
http://www.bestbuy.com/site/olspage....=1171057791920
For the receiver, most anything will work fine. Do a search for the Pioneer VSX-516. It's last year's model of the one I linked you above. Both Pioneer receivers (516 & 517) pair nicely with the speakers above.
Add a small sub, and you're going to have AMAZING sound. Even without a sub, overall, the sound quality of this setup is going to be better than any PC multimedia setup.
As for portability, grab some stands and mount wheels on the bottom. Like I said, this part is more up to you.
Stands:
http://www.bestbuy.com/site/olspage....=1063670359162
(I'm sure you could get something cheaper)
Buy all your wires online, and you'll have a cheap setup that will sound like systems double the price.
If you need any help hooking anything hook to your TV/PC, whether at the same time or not, let me know. It's not too hard, but like I said, let me know. Aesthetically I don't know what you'll think, but sound-wise, you WILL NOT be disappointed!