Anyway, for that sort of tank I would suggest something like a JBL e901 filter which is low on consumption, or an Eheim 2073 filter. These two are at different ends of the price scale and each are very good. Another option which comes up second hand reasonably priced (Usually around 40 quid) is the Rena XP2.
Sounds like you want high tech which means injected CO2. The cheapest way is to use a CO2 Fire Extinguisher and there are a couple of excellent threads on here about those setups. The equipment you would need for that though is;
* Fire Extinguisher (go for a 2kg for your size tank, it will last ages but also be a reasonable size if you go for anything up to a 4foot tank in future).
* Regulator with needle valve (I can recommend the ones by lunapet, but JBL also do a decent one, as to TMC.)
* Solenoid (so you can turn the CO2 off at night and have it come on in the day using a timer)
* Timer
* Bubble Counter (this is NOT an absolute measure !!! Use it as a guide to know if you want to turn the CO2 up/down)
* CO2 tubing (make sure its not just ordinary airline)
* Diffusion method (UP inline diffuser or ceramic disc in tank style or ceramic tube in tank or external reactor, all do the job but you get less bubbles with the reactor though it significantly reduces flow to the extent that you need a bigger filter or an extra circuit powered either by an external pump or an extra filter)
* Drop Checker (again, NOT an absolute measure but read the article in the articles section on Drop Checkers.
Thats it for CO2. You will need a heater. A lot of people are using the Hydor external heaters. The 200w one will be enough to heat your tank, but make sure that you get whichever one fits whichever filter you get... different model for different diameter filter piping
Cant think of anything else