Well, what type are you looking for? I am personally a big fan of Paints. They are really nice, laid back, great work ethics, and LOTS 'n LOTS of gorgeous color!
Get some experience working with breeds that you think you would like...that might help!
Referring the arabian and friesian question...
I have found arabians to be harder to handle. Definitely would not (generally speaking) fit into the "calm" area...friendly, yes...loving, definitely, can form a good bond, but not more so than any other horse i've known!
Friesians, are a typical draft horse, even though I haven't known any friesians super personally, i've come in contact with a few, and they were quite nice, not crazy and not dull...pretty good mix!
Basically, it depends on the horse you get, Arabians, may be hot, and a little flighty, but if you get the right one, it could be a Miss Calm!
Also, maybe you like showy horses, I can't tell, but it isn't all about looks! Sure, arabs and friesians are GORGEOUS and I would love to own one, you might have to think a little more practically if you're looking for a calm and sweet horse. (not saying that they can't be calm and sweet!)
Yeah, try to be around as many breeds as you can! You'll find out quickly which ones you like and which ones you don't!