Filter : I have some Whisper filters of that size. Although one will do for a 55G tank I have two on my 55g because the tank is long enough that one end had dead spots(still spots) with one filter. I prefer aquaclear but couldn't get them.
Heaters- the Rena looks good. You will need the 150 watt
Thermometer - I prefer the little glass ones that float or stick to the side of the tank with a suction cup. $1.99. Although the one you listed does look nice.
substrate - If you want a sand substrate pool filter sand is about the same price but much easier to deal with. Get it at any pool place. PFS doesn't have to be rinsed just poured into the tank then add water and decorations. Kiddie play sand has to be rinsed innumerable times and it will still cloud the tank for a few days. (not harmful but not pretty either

)
Unless you plan on aereating your sand about everyother day you need to put some Malaysian trumpet snails in to keep it stirred. this will prevent anerobic pockets of air from forming in the sand.
water conditioner - there are many out there and most do the job. I use the cheap wardleys water conditioner from Wal-Mart $1.97, many recommend Prime. it is a little more expensive but still very good.
Water test kit - aquarium Pharmaceuticals test kit for freshwater aquariums is by far the best test kit you can get. Petsmart has a coupon you can copy on their website and the stores will honor them.
Lights and hood - I'm not really good with advising others on lights so I will leave that for somebody else

I do have two 40watt flourescents over my 55g and the plants are doing well.
Hope that helps

Carol