Externals would be the best choice I think, more effective, less maintanence and gives more room in the tank.
Ther best external filters to go with would be an eheim I hear there second to none. If your on a budget I would suggest an allpondsolutions external great price, quite and effective also options to have a UV light in it
One who cannot love her smallest creations, cannot claim to stand before Nature - Takashi Amano
I recently asked a friend of mine about Eheim filters, she works in a fish shop, she told me they are expensive but very good, but the parts can be expensive as well, I've not got one so I can't say but just repeating what she told me.
But I do know Externals come up trumps over Internals every time, have you looked at Aquarist Classified Adverts there are a few filters for sale on there at good prices?
I have one each of the 2213, 2215 and 2217. The 2217 is rated for up to 600 litres (130 gallons) and I run that on my 5ft tank which is 265 litres (58 gallons), but with a 2213 (up to 250 litres/55 gallons) at the other end. Using both is probably overkill to be honest, but having a 14" plec in there I wanted to be sure of having adequate filtration. The 2215 is suitable for 350 litres/77 gallons and that will be running on either a 3ft/28 gallon or a 40" long 40 gallon in the near future, depending on which I set up first.
Eheim have just changed the numbering system on these to be in line with capacity, so the most recent are labelled the Classic 250, 350 and 600. Any manufactured previously under the Classic and Classic Plus 2213, 2215 and 2217 labels are a good bit cheaper at the moment, though are the exact same filters. But do go for the Plus version to get the taps and media included.