2 main types of fins :
split fins or non split fins
split fins are the hydrofoil design you're talking about. they're basically easier to kick with and give you more speed for effort used but the problem is that they're not very responsive. meaning that if you're the sort that likes to turn around and manouver a lot rather then just swim in a more or less straight line then you wont like them.
take note that split fins are terrible for snorkelling.
if you like to just float around and swim leisurely and like a soft feel on the fins, then split fins are for you.
recommended buys :
Tusa xpert zoom (medium feel good speed)
Apollo biofins (soft feel good speed good durability but expensive)
atomic aquatic (stiffer feel good speed relatively cheaper)
Scubapro twin jet fins (about the same)
Now, if you prefer a slightly stiffer feel to your fins and want something more responsive, go for the standard fins. they're good for snorkelling, very versatile, generally more durable than the split fins.
good buys :
Tusa tri ex fins (not too stiff)
Mares superchannel (quite speedy)
mares avanti tre or quatro power (powerful fins but stiff)
now for the third and not so common with recreational divers category. the jet fins. tough as hell, indestructible with obscene amounts of power and fantasic manoueverability and used by naval divers all over the world. the only problem is that they weigh nearly 6lbs for a pair and they are very hard to kick with. i've been using them for a year now (not a scratch on them so far despite nearly a 100 dives on them) and i love mine.
so there, i hope this helps you!