Heh, after having a 10 gal for like 9 years, my next tank was a 30, which I set up over the summer. And acutally my 10 gal is still by far my favorite and I pay more attention to it. "my baby", lol. I guess in comparison I tend to ignore the 30 a bit, I admit. And I do find the 30 to be a lot of work. I don't think I could handle a 55 personally.
But its all on how you look at it, and what you're ready to take upon. Many people do run several huge tanks with ease.
I suggest you have a look at ebay and aquabid for equipment, often second hand stuff is just as good and goes a lot cheaper. I'd gladly have taken a second hand canister if i found one for a good price at the time i was stocking up for the second tank.