Regular flourescent is fine if you aren't keeping corals. 35 lbs of live rock. Basically a pound a gallon. If you are on a budget, I would either order it online, or even better, post on your local forums and craigslist advertising that you want to buy some live rock. LFS's usually charge around $6 a pound, but will sometimes go as low as $4. Online, you can get it for around $2.50-$3 a pound some places, but then you have to pay for priority shipping for a really heavy box. If you know of a forum that is popular with people in your area, I would keep an eye on it for systems that are on sale to save yourself some money.
Most people advocate canister filters, but with seahorses you can get away with using an HOB. I am actually just using an Aquaclear 50 (200gph) for my 35 hex (with LR and Macros). You want the filter to turn over all of the water in your aquarium 3-5 times an hour, so for a 35 hex, thats 105-175 gph. I prefer ones where you can adjust the flow, so that it is still filtering more water than that, but just not producing a high current. Adding a spray bar will also dissapate the current so you can use a higher gph.
Hitching posts - I like macros, but you'll only be able to keep low light macro algaes with the regular flourescent lighting. Really though, you can use anything they can wrap their tails around. Fake branching corals like fake staghorns, and tall fake plants are good options. Some people just use nylon rope strung across the aquarium. Speaking of hitching posts, make sure you get a heater guard ($4) for your heater because the horses will try to hitch to it and without the guard they will burn themselves.
