Depends on what price you want, my father in law just picked up a 01 regal GS for about 15k. Nice car, accellerates like a bat out of hell and rides quite nicely, doens't handle the greatest though. Buick has a great reputation for quality, actually better then Mercedes (funny isn't it) I don't know how they do it especially as buicks are so similar to the other GM lines. The 3800 is a pretty durable engine, though it's been around for way too long.
What price are you looking at?