Got my 34 gallon tank, should I do Freshwater, Saltwater, Coldwater or....

To me, Freshwater is cheaper. I also like the variety of smaller, colorful tropical fish. You can have more smaller fish, so if more fish matters, that's a plus. FW tanks are fairly easy to me. Even if one decides to go with a planted tank, it's not too bad. Heck, if I can do it, anyone can.

Can you give us some ranges to work with? For example--I consider my 10 gallon SW tank to be my cheapest, but it still cost around $250 to get it setup right. Expected maintenance--what's the maximum number of hours you're willing to spend each week? I spend two hour or more taking care of about 200 gallons in different setups, some get 15 minutes, some get 30+. And finally--do you want several fish? One? Species only? Either type can usually be setup with a light bio-load for minimum maintenance, but many people are not happy with a tank that has only 2-3 fish in it. If you want lots of fish--FW tropical will be best. Most of the coolwater fish available will be cramped in anything smaller than a 50, so you'd only be able to have 1, maybe 2 fish total. Ditto for SW--there aren't as many options for appropriately sized fish.

Search on brackish water fish. There are several, and many of them do get fairly large--most likely he has monos or scats (just a guess). The salinity in bracksih environments varies, and many animals spend only a portion of their life in bracksih conditions, migrating either upstream to freshwater or downstream to marine.

For a tropical 30, I would go with a group of 8-9 tetras--there are a number that will work, so pick one and research it for needs and adult size. Then you can add a few more fish for variety.

I would look to getting fish in different zones. That is to say get a group that lives mid level and then a group on the bottom (a group could still be 1 fish).

My suggestionm is always to go to the fish store and see what sort of fish are available and which ones you like. Don't worry about size etc.. at the beginning, just find the ones you liek, write them down and then either research your self or ask here what types will go best together and in your particular tank setup.

Many fish at fish stores are young so they will be smaller than adult size, also many are not kept in a perfect environmental setting as the store is simply a holding zone for them. Some fish really need driftwood and plants etc... so if you don't want those then you can find that out prior to purchasing.

Also i suggest you go to the newbie forum and read the sticky on cycling a tank. It is afull of great info that will help you get started on the right foot and not make many of the common mistakes.