Correct any sump is better than none......It increases water volume, and will make things alittle easier IMO......Equipment is really a toss up, but like the advice given earlier do you homework before you buy.......At times price will be an issue on equipment, but don't let that always be the deciding factor if you buy it or not........There are so many different models of skimmers and such that it's hard to chose.....For smaller setups the AquaC would be a nice choice, but you should first decide if you going to run a system with a sump or without.....That will dictate somewhat of your skimmer choices......
Important equipment to me are RO/DI units......Alot of people are misinformed when it comes to these units, thinking they aren't that important or price is to much for water....The initial cost might seem high, but months down the road when you start to tally up what you've spent or might have lost due to skimping on this piece it will pay for itself.....Alot of people aren't aware that the higher GPD units you go you actually suffer some filter benefits......On units above 75gpd most only filter down to 92-94% of removal rate, whereas units 75gpd or down have removal rates close to 98%.......Most of the time we don't need that kind of water production that fast and think for what your loosing in filtering ability isn't really worth the size gain........
Skimmers again is a toss up.....AquaC you have a choice if you decide to run a sump or not they have different models, and if you choose to run a sump I'd recommend ASM due to personal experience and a reliable skimmer, not saying others aren't reliable as well......As a side note any tank will benefit from a skimmer, so don't let anyone persuade you that if you choose a FOWLR tank that a skimmer isn't important.....Even a FO tank will benefit from use of a skimmer....
Lighting needs really depends on what your planning on keeping.....If it's FO or FOWLR then lighting isn't as critical or costly as if planning for a reef tank.....Costs can be kept down if your a DIY or knowing where to look for quality equipment......MH's aren't a must for reef tanks, and they can be run with T5's with the use of the proper reflectors......IMO if you can't afford or don't want MH's then T5's would be the lighting source I would look into......
Heaters there are so many on the market, but I prefer the titanium heater over the glass, and look for heaters with temp controller as well.....My personal favorite is Jalli, but for glass heaters I always fall back to Ebo Jager heaters which have been around for ever and very reliable.....
Pumps are hard to say, but depends on the setup you have and what your planning to keep.......You have to look at tank turnover to get an idea where to start and the you have to take into account overflows and such, so there's a whole other realm to look into.......
Take your time and do your research and ask lots of questions......and just want to WELCOME you to the boards!!!!!!!!!