I agree the wet pet will probably get old for you. Eventually you may regret only having one fish in the tank, once u see more that u like (but cant add). The 40 breeder is a nice classic size for several fish. Low height means lots of surface area on the bottom.I'd avoid the single wet pet, its gets boring IMO.
I say go for a small/medium cichlid community, then you get the interaction and feel good from knowing they're in an appropriately sized tank