Hi all,
Ideally I'd go for the Classic 2213 & 2215, 2 of each. I'd also supplement these with a powerhead/sponge for each tank, gives you a back-up and some more flow. I also think that the 2213 would just about give you enough filtration for both tank sizes, in which case you could buy 4 of these, and a larger power head if you wanted more flow. Partially I think the 2213 would do as I'm fairly keen on keeping bulky organic waste out of the filter, so I'd put a coarse sponge on the filter inlet. Have a look here for the reasoning. <
http://plecoplanet.com/?page_id=829>.
Another option to go with the "Eheim Classic", instead of a sponge filter, would be the "Eheim Liberty" 2042 HOB. If you got these I'd throw away all the little filter inserts and 3/4 fill them with ceramic rings. The advantage of the HOB (or any other trickle filter) is that the water is very well oxygenated. For this reason I'd run the venturi on the powerhead (if you have the powerhead at the bottom of the tank you will need to pump air down to the venturi fitting with an air pump.)
Have a look here:
http://www.plecoplanet.com/forum/showthread.php?p=37182 &
http://www.plecoplanet.com/forum/showthread.php?p=56938
cheers Darrel