You need to answer these questions -
1) How many sources am I going to be recording from at once?
2) Am I going to mix down to an external device (like stand-alone CDR) or am I going to be mixing / mastering internally on the CPU?
If the answer to #1 is one, and #2 is internal, you might want to skip the mixer and buy one good mic pre-amp. If on the other hand you are going to be recording a large rock band live, then you want to go with a mixer with lots of input channels - something like Behringer can get you lots of inputs for cheap. If something in the middle, you want to get the best sounding board that fits your requirements and $800 budget. It just depends what you want. If you go used, you can get a better sounding board for your $$$ but will have to check it very carefully.
For the record I bought a Alesis Studio 32: 16 inputs with mic pres, + 16 tape returns, 4 sub-outs, 4 effects sends (2 usable on any one channel). Paid $760 + tax for it new.
