I have the opposite problem to you, Adamas, in that my hair is very curly and takes bloody ages to straighten- and isn't actually straight when it's done- and chemical relaxers were just a disaster, so I never bother. I'm considering wigs, I don't know whether to go for the red headed Rihanna look (the straight look, rather than the long 'fro which I have naturally anyway) or the Nicki Minaj/Lady Gaga look. I could rock both, I suppose.
I know that particular shade of red suits me as I've died it that colour in the past, but trying to work out what shade of blonde to go for is a pain. I'm having to wade through lots of stuff about "cool" and "warm" skin tones, spring and autumn skin tones etc, but have settled for a honey blonde.
A friend of mine takes to wearing
weaves when she wants a change; synthetic hair holds the curl much better than natural, but you have to make sure you're getting good quality stuff and it doesn't last as long as natural hair, and you'll need to have some hair of your own to attach it to in the first place. The upside though is it can't be pulled off like a wig and won't slide about.