I've just set up a new 125 after breaking my 150 during a move, so i had a chance to start over. I tossed around ideas like you're doing, but i decided that i wanted a tank with alot of movement, so i opted for a couple of schools of small fish. I have 15 zebra danios (dont knock them, i love the little guys), 15 glass barbs, 10 peppered cories, three angelfish, and one fat lazy common pleco. None of my guys minus the pelco and angels should get over 3.5" and there is always constant movement in the tank. Its fun to watch them all interact with eachother! Just my opinion, but go with smaller fish, its a blast!!