Ok, so you want to play records, CDs, Tapes (cassette?) and stream from computer. This is no problem as there are many integrated amps (amp + preamp) that would allow for this and fit into your budget. Some have internal DAC, some have internal phonostage, and some provide both. A primary question is your need for amplifier power which is dependent on speaker choice and room size.
As millercarbon stated, the Klipsch speakers are very efficient and therefore don't require a great amount of power. I think the first thing you should try to determine is if you wish to build a system around them. There are forums specifically for these speakers. You may wish to explore them.
If you purchase a DAC with USB, coax and toslink input, wether internal to an integrated amp or a separate unit, it would serve both computer streaming and CD playback.
Unless you want to digitize your vinyl collection I would not choose a USB turntable. I once considered this and quickly decided against it. Must be done in real time and I decided If I want to play vinyl, then play vinyl.
Match speakers to room, partner amplifier to speakers, consider sources during amplifier selection. consider internal vs. external DAC and phonostage. Though I don't believe that cables should be the last thing to worry about, I do believe they should be considered last. Start with budget cables.
Are you willing to purchase used?
