An audio interface

[Adach]

i use an Onyx-820i as my interface, the thing is amazing!

[wytenoize]

M-Audio Fast Tracks are good if your only using monitors. the only downside ive found is an ugly hum when the guitar gain is right up which you can roll off in EQ anyway if you do ever decide to record something(it could have been caused by bad leads though i wasnt too sure). its a nice unit for a basic setup at a damn good price IMO. as long as you position them properly and run through ASIO and not some shitty driver you will get the clean sound your looking for. i find most of the quality is inside your monitor, feel free to shut me down on that.

Prices jump when you start looking at firewire connections and extra in/outs.

[JBlongz]

Don't know if you bought the firestudio yet, but TC Desktop Konnekt 6 is $100 less on eBey for the same quality. I use in one of my production rooms.

TC Electronic Desktop Konnekt 6 | Sweetwater.com

[Satori]

I'm afraid of presonus after dealing with a crappy firebox. Apparently, a lot of other people had the same "red light" issue. I switched to Focusrite and have been happy.

[Resonator63]

I use an Audiobox 22vsl nice solid unit and works a treat.