For me there's 2 ways of getting inspiration. One is to start listening to stuff other than your normal fare. If you usually just listen to rock and blues I recommend country, jazz, folk and flamenco as the best sources of inspirational fretwork. Way back, I just used to listen to metal/hard rock speed merchants. Since then Ive found a lot more to inspire me by listening to country pickers like Albert Lee, Jerry Reed and Chet Atkins. Some of the top progressive bluegrass flatpickers are also pretty awesome, especially Dan Crary and Tony Rice. Also dont just listen to current and recent stuff but try and trace your way back to the originals like Charlie Christian, George van Eps and Django.

Second approach I use is to try all sorts of different tunings. If you're one of those who just sticks with EADGBE you're missing out big time. Recommended listening? anything by Leo Kottke, Martin Simpson, Don Ross or John Renbourn for starters.