Ryan,
If you're going to do it right the first time, my suggestions would be:
1. Get MH lighting. Don't bother with PC because (as Seahorse) said, if you upgrade the size of your tank, your PC light may not be long enough and will need to be replaced. MH can be used, and if not enough you can add another one. For now, I would get 1MH 250W fixture going for corals (especially if you want to keep some SPS, I know you will eventually want to!).
2. Get a good skimmer. If you have a sump, even better because you can get an in-sump model. I run a Remora Pro on mine, and it's a huge eyesore although it's probably one of the best HOB skimmer on the market right now. Also, the pump is unsightly in my tank and would look even worse in a 33G. DON'T GET A PRIZM or SEACLONE!!!
3. Go with Tunze streams. You can probably put one 6060 in your tank if you mount it high enough. When you get a bigger tank, you can always add more.
All of the above is what I eventually upgraded or want to upgrade to. I spent so much money cheaping out or buying something that would only accomodate what I had then, and not what I might want in the future. I would have saved so much $$$$$
If only I could do it all over again......