getting a 100g+ tank for b-day

What kind of cichlids and how many?

In a tank that big, separating mechanical and biological filtration is a real plus, unless you go with a sump system that does both.

I have a 180 that is moderately stocked (it used to be lightly stocked, but my kennyi have bred like rabbits...) and I use 2 prefiltered HOT Magnums, a prefiltered Eheim 2228 Professionel (packed with Ehfimech only) and an Eheim 2229 wet/dry packed with Ehfimech and plastic bioballs.

Until the kennyis got out of control, the filtration was just about right. For a 100, I'd go with a couple HOT Mags for mechanical filtration and large canister (e.g., Eheim 2028) packed for bio-only.

You could go with some big HOT filters (e.g. Emperor 400s or Aquaclear 500s), but I prefer canisters on a tank that big.

Jim

I have a aunt that used about 3 of the penguin's highest models for her 150 gal that turned out nice and i forgot the names of those filters. You could go with a in-line canister filter such as a Ocean Clear filter, since they can handle really big aquariums.

I was going to get a Ocean Clear for my 240 gal, but instead i got a Bio-rocker because it was a wet/dry and i wanted something that was meant for a tank that was over 250 gallons.

Ive always preffered HOT filters for their simplicity and ease of maintenance....having said that i use 2 Aquaclear 500s on my 100 gallon tank and its PLENTY of filtration. The emperors would also be a good choice, however ive found them to be a bit more noisey so i dont use them. Silence was the key as this tanks in my bedroom and im a VERY light sleeper and the AC 500s seem to be pretty darn quiet.