Like I said, you probably should have some experience wth freshwater, because like I said, the easiest animals to keep are often undesirable. It is wise to remember what you have said in the past before saying something that, in effect, contradicts it.
I actually run my marine tank very similiar to the way I run my freshwater tanks, and the only living creature I have had a problem with is L.T. anemones(grr...
). I do not use RO water, I do not do water changes, and as of now and a few months past, I do not have a protein skimmer. The only things I do differently from FW to SW is use refugiums instead of filter material, use LR only, feed frozen food only, and heighten algae and water top-up maintainence.
Sure the maintainence for most people in SW differs considerably from that of FW, but the experience gained from keeping FW fish is highly beneficial. That is, unless, you want to have a tank full of damsels only and a snail or two. It is a highly valid point; it would be extremely costly and difficult for someone new to fish to attempt and keep something highly desirable such as an angel, tang, or butterfly, whereas someone with experience with freshwater who has kept an elephant nose, discus, fire eel, ect., would have a far better chance of keeping the picky fish alive.
There once was a very heated discussion on the importance of RO water, and, frankly, I do not want that started again, so although I probably could, I wont. Everyone knows my opinion.
-Lynden