I don't use fancy filters or anything either, all by hand.... I use a mix of gimp and photoshop, and I prefer photoshop, but that's because Photoshop is what I learned on... and I get a free copy of CS3 (and 4 when it comes out) through my school.
But yeah, I start is PS and end in Gimp, usually.
I've said it before, but I'll sat it again... I really thing the key to a good texture is using layers... It allows easy and quick editing, which means more time on creative ideas and less time on correction.