I find myself resorting to the pentatonic scales for almost all of my solos. Anyone have any other ideas for solos? I usually use a pentatonic minor scale for soloing over blues. Any other scales or ideas for improvising would be appreciated.
Well, if the pentatonic works, Dorian often works too. Dorian is a great scale for blues rock. For the darker stuff, just plain minor (aeolian) is great too. Go look at the lessons on here about scales and modes to get some ideas for other scales.
Mixolydian (major scale with a 7b) is also really good for blues. Remember that you can also add the blues note (4#/5b) to the pentatonic scale, and even if just used as a passing tone it can sound great. Arpeggios can be really useful, but in blues you'll most likely be taking a few notes from an arpeggio and incorporating it into a line, instead of playing the whole thing.

Edit: Are you talking about just blues, or improvisation in general?
I was talking about blues, but any good scales that you think are useful would be great. I play some rock as well. Thanks for the responses.
This is what In Vein was talking about in A minor.

Whilst diatonic scales are great don't forget you can go the other way too - and use arpeggios/triads.

For a lot of blues you can use both the major and minor pentatonics over the same backing track too. It can be fun switching between the two in the same solo - using the major 3rd as a transitional note to go from minor to major, and the blue note to go back is an easy way to start off.

If you want to understand more about scales its worth learning the major scale (so you understand how its constructed in terms of notes, steps - WWHWWWH - and intervals) - pretty much any other scale you'll want to use can be derived from the major scale so understanding it makes all the others a whole lot easier to get your head around.