I have used the Cascade 1000 on a 65g and currently use two 1500's on my 120g. They are a great budget filter with a ton of room for media. They do however have a by pass issue that can be reduced by wrapping a strip of blue filter pad around the top and bottom basket. Mine have never leaked and the only thing I have replaced was an impeller just because it was making a little bit of noise. It was still working just fine. The unit is very well built for the money.
Pair up this filter with the Hydor ETH in line heater and you have a nice combo.
But what ever you do go with the largest one you can afford. The ratings of what they handle is kind of a joke. They are not the best at picking up large debris (you still need to gravel vac!) but are good for bio or chemical media.