Like Stokie said, it all depends what kind of diving your into.

I've only dived in the Carib, and water below 26°C for me warrents a full 4mm+ wet suit for 100 foot dive. In the summer, the water is around 27°C at 100 foot and you can get by with a carib shorty wet suit (one piece with the arms and legs cut off).

Personally, I'd go to a dive shop for your first outing. You need to try on the bcd's and find one that fits properly with the bells and whistles that you want. Regs are a personal choice (i've been through 4 sets just on this island alone).
Like everything, there is a tonne of choices mixed between 'crap' to 'excellent'.

If your going for more wreck diving (only if you have the cert), then you have to buy equipment to match it...

Side note: its best to at least get your cert up to 'rescue diver' if your going thru padi. Most people don't feel confident until that cert, and its nice to know what to do if your buddy is in trouble at 100'.

Kris