I would go with an external canister filter... personally I own a Rena XP3 for a 90g and Eheim 2217 for 75g so I can only speak for those brands.
I'm not sure of price difference, since I got both mine used, but I'm pretty sure they are in the same price range.
I like both, but they have their pros and cons...
My eheim is completely silent... sometimes I think it's not even running!! But I find it to be more difficult to prime just because you have to suck on one end of the hose to get it going... or sometimes you have to pour water in the tubes. You also have to make sure you use the easy disconnect valves to block the pipes when you go to disconnect everything or you have water over the floor (been there, done that... now my carpet smells like fish
) But I like it's circulation, it produces a nice, strong current that my fish really enjoy.
I've heard Renas are very very silent but mine has a little hum that just won't go away. I wonder if something needs to be replaced, but I don't know enough about them to go and replace parts.
Anyways, I think it's my favourite of the two. I like the easy latching handles on the top and the super easy priming. Just latch down the top and it fills up all on its own. You also don't have to worry about the tubes spurting out water when disconnecting 'cause it cuts off the water on its own. I just wish the flow was a little higher...
Anyways there's my 2 cents. I only use canister filters on my bigger aquariums so not sure which one you'll need for a smaller tank. Best of luck.