Sound components for a computer & TV

I'm building a new system with the intention to use my existing Bose speakers with a new sub and receiver for a pretty small room. Here are some components I'm considering plus the speakers I already have:

• Bluegears sound card (http://www.newegg.com/product/prod [...] 6829127002)
• Onkyo SR304 receiver (http://www.amazon.com/Onkyo-TX-SR3 [...] 453&sr=8-2)
• Polk 10" sub (http://www.circuitcity.com/ccd/pro [...] merRatings)
• Bose 201 speakers (http://www.amazon.com/Bose-201-IV- [...] B00006HO4Y)

I don't plan to expand beyond 5.1 sound but will probably look for new speakers down the road to fit into this system. All in all, do these choices make sense together? Do you have any better recommendations without breaking the bank? Can my oldish speakers work well in a 2.1 setup for the time being? With these parts, is a sound card worth buying?

Thanks for your input.