Recommended pre-amp or power amp?

[Speederlander]

I want to feed from my computer into my stereo. I have Infinity Alpha 50's and the matching center channel. My old power amp is long dead and I want to upgrade to something modern and input friendly. What do people recommend both on the amp/pre-amp or integrated amp side and soundcard side? This will be used for all sound from the comp, from music to movies to games and everything in-between.

The budget is under $1200.