This would be my checklist...
1. T5 High Output light fixture 2 foot or 4 foot by either 6 or 8 bulbs...
(the length and number of bulbs will be dependent on how many plants you plan on growing at one) If you are planning on just 1 or 2 then you'd get away with a 2 foot x 6 bulb with 6500k bulbs... If you plan on growing 3 or 4 get a 4 foot x 6 or 8 bulb with 6500k bulbs...
(the reason I say only 1 or 2... Or 3 or 4 is because you can get through your entire veg cycle with this fixture)(if just using for seedling strictly then you can get away with whatever size that will cover the width and depth of your grow space)
2. Get yourself 2 or 3 - 65watt cfl spiral bulbs. Also get the same number of plain sockets that are pre-wired with a wall plug. Just make sure the socket can handle whatever wattage you plan on using for a bulb so you don't melt the socket and burn your place down!
3. GET A ROLL OF MYLAR!!! I cannot stress this enough! Without some sort of reflective material on your wall you will be wasting a lot of light. This stuff is cheap and easy to work with. A 54" x 4' roll costs me around $23.00. Worth every penny especially when using T5's because florescent lighting doesn't penetrate with light to the bottom or lower portion of your plant. Also why I said get a few cfl's and sockets to hang... All of this will make a notable difference during veg which overall affects flowering. Once you get yourself a metal halide you won't need extra bulbs unless you plan on topping out at a pound per plant.
4. Oscillating fans are also a necessity! They promote stem strength and also help to keep hot air moving from the bottom of the group space, and as long as an out take or a way for trapped hot air to escape is available, then it will also help to cool the area.
5. Pick up a small fan that you can face upward or across pointing toward your light fixture. It will also help to keep your lights cooler.
6. A few disposable grow tray liners. These are only like $3.00 for a 8" x 24" tray and are the best to use while in the seedling stage. You can pour water directly into the bottom of the tray and your seedling will suck up the water as needed. Then you simply pour the runoff or leftover water into a drain wipe out and place the seedlings back into it and under your lights.
7. A table, single step step stool... Anything you can use to keep your plants raised off of the floor. You don't need crawlers(bugs that crawl) having easy access to your garden.
8. Grab a timer or two... One to run your lights and one to run your fans. This will give you ease of maximum control with having to do very little other than feeding and checking in.
9. Power strips are great IMO... If your power goes out you will not have to worry about any harm to your electrical equipment. Plus it's awesome when you have multiple things to plug in at once. If the electrical outlet is far from the grow space... Buy a heavy duty extension cord. Don't buy a cheap flimsy extension cord and I cannot stress this enough either. A better quality, heavy duty extension cord is made to take larger loads of electricity without burning the wires in the cord out and potentially causing a fire.
10. Digital Thermometer/Hygrometer combo unit. They sell at stores such as Walmart for around $10-$15. Completely necessary to be completely aware of your grow spaces environment. Heat should stay between 70f - 80f.
11. Spray bottle. This will be for misting your seedlings to provide the moisture it needs to survive. Not necessary but I would still recommend one.
12. Distilled Water. Only for the seedling stage. First week or two is fine.
13. pH Meter. Essential in making sure your plant is able to take up nutrients and/or water. Check your waters pH before every feeding.
14. pH Up & pH Down. Also essential in adjusting the waters pH.
15. Rockwool cubes or jiffy pellets. I personally like rockwool cubes because they don't retain as much water as jiffy pellets do. Over watering could easily be the destruction of a plant... Especially a seedling!
16. Also figure out a way to hang your lights.... Chain, hooks, or retractable hangers made specifically to hang lighting.