Gator cycle in G.ville is pretty good.... Same owner for a LONG time and a lot of the mechanics have been there since I bought my bike in 2004. Can usually squeeze you in if you live 40 miles away (me) and need some thing done while your in town. Good selection of Trek & Gary Fisher (and another brand, cant remember).
http://gatorcycle.com/
But lately .... I have been dealing with a mom & pop (ok more like father & son) shop that opened up in Palatka. Closer & very reasonable repair rates. Plus I see the owner out riding regularly...
For cheap used parts in G.ville...... Spin Cycle... They usually have boxes of junk you can look through.... Comes in handy sometimes.