Flash recommendation please

I'd like to dabble/experiment with portrait style photography but the only flash I've ever used is the built-in one. I don't have a fortune to spend and really can't quote a "budget" per se, but I'd like something that wouldn't be too terribly expensive yet still allow me to get an idea if this is an area I'd like to pursue. And I also like to do alot of outdoor stuff if that matters at all.
Thank you.

If you cant quote a budget, then its difficult to be any help. Your best bet would be to try to find a used 430ex, not the 430exII. You can find them under $200 on the sell forum occasionally. There are also some sunpak models that have ettl that people report good things about but I dont know which ones. Do a google search for sunpak and ettl and you might get some good ideas.

There have been quite a few 420EX flash units going for about $120 used lately on this site's buy/sell forum. That would be a great starting point. You could use a long ETTL cable to go off camera if needed. 430EX would be better as it also has manual flash controls, but it is an extra $75-100 and I have yet to use my manual controls on mine.

If you just want to go the strobist route, then I would visit the strobist blog for rec's on flashes. He has some extensive articles on good manual flash units.

Your best bet is to stay with new/used Canon speedlites and not go with third party units. Basic reason for this is compatibility and the event you upgrade to another Canon DSLR.

I have a Sigma EF-500 DG Super that works well on the Canon bodies. I've used it on the 30D, 40D and 1D MK III. It's not too expensive if you buy a used one like I did. Not as slick or as well made like the Canon models, but it works.