The Xbox won't up convert the sound!!! I'm not kidding you man. Once I hooked an external amp up to my F2's, (this is the second one), it really brought them to life if you know what I'm saying. My amp only pushes 90 watts to them, but the difference in the amp and my receiver is night and day. I wasn't thinking about doing it, but if I was wanting to upgrade the F2's, the amp would have easily changed my mind! I don't know if you read my review when I put the amp on them, but I said I think I have the best sounding synergy system on the forum now; and I meant it!
Try looking at Clist, audiogon, ebay, etc. I paid 90 woppin bucks for my ROTEL. Just be patient, and make sure you have the cash in hand. I watched the ROTEL on c list for about 3 months; and eventually he lowered his price to a negotiable 150 bucks. And the BD player. I'm not sure which one made a bigger diff. The amp or the player. But if you get these two things, I guarantee you your system will be on a whole new level. After these two things, then upgrade your surrounds. Are you running a sub at all?? If not, keep the surrounds for now, and get a sub first. Even before the amp or BD player............. You know what they say; your systems only as good as its weakest component!