If it's gonna be a one time thing, you may just wanna buy an all-in-one kit from Sports Chalet, Big 5 or something like that. If it's something you think you'll wanna do regularly then it's worth it to spend the extra money to get good gear.
Mask: Atomic Frameless, Atomic Subframe, Mares X-Vision, Oceanic Shadow, Cressi Big Eyes. Fit/comfort is most important, but all of the aforementioned are very well-regarded and worth checking out.
Snorkel: Tusa Platina Hyperdry II, Aqualung Impulse 3. I don't even use a snorkel anymore when diving, but sometimes I snorkel/freedive and I'm glad to have a good snorkel. I have the Tusa and love it...but I've also heard a lot of good things about the impulse.
Fins: I would also recommend a paddle fin. Hollis F1, Mares Quattro, Scubapro Seawing Nova, Mares Volo, and Mares Excel+ would all be good fins to look at.
@iztok
I just got the F1's a couple of weeks ago and love them! Powerful, precise, and even easier to kick than my Quattro's were...great fins.