I have fine yet thick, naturally wavy hair that I either flat-iron and wear down, or leave wavy and put in a ponytail. (I've never been able to make it look good wavy down, and I can never get it straight with a blow-dryer and straightening cream! Especially in the humid summertime!)
I like L'Oreal Hot Straight -- it helps protect my hair from the flat-iron and as an added bonus, it's a very good anti-static product! (Since my hair is so fine, it's full of fly-aways without some sort of product!)
I also like Herbal Essence Flexible Hold hairspray, however I haven't been able to find it lately (maybe it's discontinued?) so I've been using Dove Flexible Hold hairspray which is similar but doesn't smell quite as good! I like flexible hold hairsprays because they keep the fly-aways and frizzies down without making my hair crunchy! Even when I wear my hair down, I always put a little spritz of hairspray along my part to keep the shorter fly-aways down!
Those are really the only 2 products I've been using lately!