Basic Preamp - suggestions?

at that price range, for a multi-input preamp you're probably best served with an adcom--either their gfp or their gtp400/450/500 units, which have integrated tuners--easily available under $200 and quite serviceable.

Awesome. I will look into those Adcoms. How are NAD preamps?

Do people have opinions on whether buying a dedicated preamp is better than just using a decent receiver as a preamp?

My setup is

Linn Espek speakers
Oppo 970HD (cd transport)
Rega P2 turntable
Rotel RB 1050

You asked for used, but if not absolutely opposed to new, the Maverick Audio tube DAC /Preamp /headphone amp might be just the ticket. It's $200 and you could roll to a better tube later down the road ... like a GE 5-star 5670. With your set-up, you can go digital-in with the Oppo, put a basic Pro-ject pre between the Maverick/Rega and you're in business without dropping a whole lot a coin in the process. In addition to headphone amp, the Maverick D1 even has line-in for iPod. I have this great little "Swiss Army knife" component anchoring my office system.

I would look for a PS Audio 4.5 or 4.6 preamp. It is passive or active has an excellent phono stage that can handle LO moving coils and it's pretty versitale and has an outboard power supply that's twice the weight of the preamp. Even the PS IVH is still a pretty good unit and
is easily found under $200. There are several hafler units out there DH100 or DH101 but the PS still has a better top end than the Haflers. Good Luck