My 77 Hagen has been running sumpless for just over 3 years now. Rena XP3 canister filter (empty baskets except for a bag of carbon) for a little extra water volume, hang on air driven cc skimmer and IMO the most important, two MP40W EcoTech VorTech powerheads for flow. As an ATO, I use a glass wine carboy pressurised by an air pump on a timer with a mechanical float switch to control the level in the display. In the switch to salt water, you'll also want to invest in a RO/DI system for pure water, otherwise you'll need to find an alternate source and lug the stuff home in large jugs. Depending on what you plan to keep, lighting requirements will need to be well researched but to get started cycling etc., some flourescents will probably do nicely.
If your 77 is a Hagen like mine, you may wish to look at drilling it for overflow/return, then you'll have the option of using a sump straight away. I've checked the Hagen tank web page FAQs and it states all their tanks use non-tempered glass, so drilling should be no problem. Although running sumpless is actually a bit less complex, I plan to upgrade to a larger tank with a sump in the basement..... soon, I hope.
Skimmer
ATO container
ATO float switch
