Ahh, je comprends! I don't use gradients as such, but a lot of the textures I like to use have gradient-like effects to them.

And ooh, *feels honoured* =D

Recently discovered that there's a sharpening feature in Gimp outside of teh brush (i.e. can uniformly sharpen the whole image), but I've not used it yet. I know photoshop is a heck of a lot better than Gimp, but Gimp is free and it took me so long to get my head around that I'm rather partial to it now!

You can use layer masks in Gimp - I saw a tutorial that featured them a while back - but I've not tried them.