I spent $425 on a used Musical Fidelity A220 integrated amp, and I love it. If you're running the XBox using a digital connection to your amp, you're probably going to want to find an amp w/ digital inputs... the amp I listed above doesn't have digital inputs, and my former tube amp didn't either.... would need to add a DAC.... DAC is going to cost some scratch... or you could rely on the analog output from the xbox.
at any rate, the way I see it is that you just bought new speakers, so you don't want to replace that. The XBox is quite unique in its abilities, so you probably don't want to replace that... which leaves amp.
The guy I bought the speakers from was running them through a solid state amp that really made the speakers sound great. How does an amp integrate with a receiver? Obviously I need to upgrade my receiver at some point, but would my current receiver interface with an outboard amplifier properly? I'm just wondering because the receiver already amplifies the signal so how would it deal with being amplified twice?
When I suggested it, I was talking about replacing your current receiver. If you look on the back of your current receiver, look for a pre out. If it has a pre out, then you can run that into a power amp, and the speakers from the power amp. If you were going to replace the reciever, you'd do one of the following:
a) a preamp + poweramp setup (which would probably be out of your budget)
or
b) an integrated - which is within your price range, and is a preamp and poweramp integrated into one unit - its basically exactly like a receiver, except I *think* a receiver is different solely because it has the ability to receive AM/FM radio. An integrated amp is basically a reciever minus the tuner part.
In regards to an outboard DAC... yeah, I'll have to wait to drop some cash on that. I do plan on buying one at some point (Are they single input/output? I only have one device anyway so I suppose it doesn't matter all that much).
they have a variety of different ones. I have seen ones that have a coax and optical input with a switch to switch between the inputs.