i second what wareagle said...I personally dont like getting the all in one things like nano cubes, bio-cubes, all those...I like to actually pick and chose what filters, lights, tank shape that i want...all that. But then again, i like to experiment w/stuff, which is kinda how my nano is...2.5g with a pound of live rock from the lfs, and another 2 pounds from when i went snorkeling. I've also got a whisper 20 HOB filter on it that looks totaly huge for it lol, but its such little flow for that filter that imo, its perfect for a 2.5.
Lighting it is also a piece of cake, tho i've tried a few different things w/that too. But right now i've got a coralife mini pc bulb (the 50/50 one that screws into any regular lamp) but i plan to get the 20 watt one, cuz the 10 isnt really very bright...i'm sure its enough light to possibly grow what i got, but i cant really see it.
so what type of tank are you lookin for? One that can maybe hold a couple small fish (like a 10 or 12 gallon nano) or something like my 2.5 which isnt good for any fish, but just for corals and inverts...i plan on getting a mantis shrimp as soon as i can find one for free lol.