nice thread, kikuchiyo. this should be made into a sticky, as it has great guidance for newbies. I know this is 2 years old, but I think it's still good.
One thing with the bettas and over-strong filtration; Turn off your filters during feeding times. It's what I do when I have some particularily lazy fish that don't feel the need to chase their food. Unplug (or kill the power strip) while you're feeding him. It'll make life easier on your betta, and certainly won't hurt any.
I ahve the hagen waterhome 5 (not econo) and its awesome! It's a bowfront and comes with a TopFilter (some sort of wet/dry trickle filter) which works really really well. It also has a 13 watt CF ballast intergrated into the hood. My colour is grey with a terracotta top
I use a 25 watt Whisper Mini for the ehater and its really cool looking =)
those nano bowfronts are really great
I like the bowfront ebcause it makes the tank look a little bigger but I do admit it distorts the view a bit making scaping a touch more challenging.
small tanks are awesome =)
I have a dwarf puffer in my tank.
Small tanks like 2.5-5gallons are a lot of fun and can look really pretty and be awfully cheap on ferts/co2 but they are much harder to maintain.
I'd get several different stages of algae in my 5 gallon in the time it takes my 80 gallon to go through one.