Any saltwater guys out there? A couple questions here.

As some one that keep reef systems, I must respectfully disagree with some of what was posted previously.

First, here is my advice to anyone considering a reef system -

DaveK's Standard Lecture #1 – Advice for people new to the hobby

The very first thing you want to do, before you spend any money on equipment or livestock, is get yourself a few good books on state of the art reef systems. Then read and study them, so you have some idea about what your are doing.

Here are two to start with -

The Conscientious Marine Aquarist by Robert Fenner
The New Marine Aquarium by Michael Paleta <---This book has an especially good section on fish suited to someone starting off in the hobby.

This is information that you can not easily obtain from the net. While it's out there, it's all over the place, and there is a massive volume of information.

Once you get that done, plan or rethink your system. What do you want to keep? Do you have the necessary equipment? Do you have the knowledge to keep the livestock you want? Do you have the time to dedicate to keeping a system and it's livestock?

Many salt water fish, corals and inverts often have very specific requirements. Some are extremely difficult to keep alive, even if you do everything right. Before you get anything, research it, and be sure it will work out in your system.

Lastly, you will find that most LFS people are clueless when it comes to SW systems. Verify their advice, until they prove otherwise.

Now as to some of the specifics related to reef systems and previous posts -

First, there really is no such thing as a budget SW system. Yes, you can save some money with DIY projects, buying used equipment and so on. Even so your going to invest a lot of money. Most desirable fish are about $20 up, most corals start higher. You can not casually afford to loose livestock. If your going to acquire everything from scratch, expect to spend about $25 to $50 and up per gallon of water in the main display tank by the time your more or less complete. Figure that a 30 gal tank, completly set up costing about $750 to $1500, and think toward the higher end.

While not an absolute requirement, if you plan oh having fish, I would highly recommend a skimmer. Yes, people do systems without them, but a skimmer is highly desirable to a point where you should have one on any system that you plan to keep fish in.

On FO (fish only) systems - Yes people do set these up. IMHO they are a disaster waiting to happen. Most people are far better off doing a FOWLR since they will maintain a much higher water quality. I don't know anyone in the SW hobby any length of time that keeps a true FO system, but I'm sure there are still some.

The not to overstock point made by several previous posters is extremely important. SW fish need space. The typical rule of thumb for SW is 1 inch of fish per 5 gals of actual water. When you compute this you should use the adult size of the fish. So a 30 gal tank should have about 3 or 4 small fish.

Anemones come in all sorts and sizes. In a small tank you want to restrict yourself to what are known as Zoas (Zoanthids) and mushrooms. The larger predatory anemones, like the ones you see clowfish hosting in, are out of the question in a small system.

Most other inverts on an individual basis are ok as well, but some will go after each other. I'd avoid crabs, except for hermits, and predators like mantis shrimp. Other shrimp are generally ok.

On http://www.reefcentral.com/ - This is the largest reef site on the net. Read it for advice, but be forewarned that they have, IMHO justified, reputation for being really harsh to new people in the hobby. Before you post anything make sure you read the sticky threads and FAQs, otherwise you'll just get referred to them. You might want to consider http://www.reefsanctuary.com/ which is a lot easier on beginners.

The last important point I want to make is that lots of experience in FW systems, even with planted tanks, give you some basics, but the way you do things in SW is completely different. For example in a planted tank we love canister filters, and we add ferts to get plant growth, and we restrict lighting. In SW systems, canisters filters are almost considered evil, and often the recommendation is to replace it with a sump. Adding ferts is never done, since the goals are to keep nitrate and phosphate extremely low. Lighting over corals or similar inverts is extreme. What is considered way too much in a planted tank is considered minimal in a reef with corals.

Now with all that I hope I have not scared you off. SW systems can be very rewarding, but you have to put a lot into one to get something out. Note the number of "retired reefkeepers" we have here, with some of them looking for a much easier system to keep.

Happy reefing.