Bends are always a must. There are actually notes which sound best bent, at least (generally) fit better when bent, but unfortunatly I couldn't help as I never lernt which notes they were, I just went for any...
I was playing a 12 bar blues with my dad on rhythm guitar, and suddenly I broke out of the pentatonic scale into a Phrygrain Dominated (Spansh scale), which had some pretty wild affects. Try borrowing notes, or a run of notes, from other scales if you don't want to go into a whole new scale, see what happens. The key is, as with everything, to experiment, try new things; as the saying goes "Don't practise what you know, practise what you DON'T know!"...I've found it's the quickest way to learn.
There's a tonne of other things you can do to spice up your playing, but I'm afraid that's my two pence worth. Hope it helped, good luck!
While I remember though, think about taping yourself or recording your playing on your computer, ask people what they think, the majority of people at the forum with gladly give you constructive critism or praise. Okay, now I'm done...