Every once in a while I like to shake things up a bit with my avatar, usually nothing major, just a change of pace. Often it's the hair. I have a few favorites, but I quite a few different hairs, most of them some shade of red, though occasionally I go through this crazy color matching phase of outfitting (IE, blue shoes, pants, shirt, and hair).
I generally don't change my shape. I've grown pretty attached to how I look. I always dump my numbers into any OpenSIM grid I visit so I know I look right and I've used it for pretty much ever. I don't believe I've ever bought a shape that I used regularly, I just made my own and tweaked it over time as I decided I didn't like parts of it. The latest tweak was in the nose.
One thing that always bugged me, and it showed up a lot in screen shots, was that my nose had this weird clipping artifact at the edge of the nostrils. I fixed this by making it larger, and I'm pretty satisfied with how things came out.
I've also made some other parts larger as well... I'm blaming a long time in world friend for being a bad influence...
I bought a pair of mesh breasts, specifically, Lolas Tango breasts. I have to admit, it seemed like a ridiculous thing to do at the time but the end result is pretty satisfying.
I've always been really bugged about how Second Life handles clothes and breasts. Mesh helps a bit and you can get some fakey cleavage tattoos that sort of work. Still, the "painted on" effect has always been a pet peeve. This fixes that.
I also managed to blend it surprisingly well with my skin. I forget where I picked up this skin but I'm rather fond of it. There are three base categories of light, medium and dark with like a dozen shades inside. To complete the effect you get a selection of tattoo layers that I'm pretty sure are just gradiants to transparent to help blend things. You can tell in some light and some angles but it's not any worse than the normal clipping issue of the Avatar mesh itself.
I also will admit they feel a little comically oversized. I'm ok with it though. I like a little more, "cartoonish" look for lack of a better term. The only real problem is making them work with my clothing. There are several built in clothing appliers for generic flat looks that work pretty well but I want to look into the included developers kit to see if I can make some better tops to add.