I'd recommend Harris brushes personally. Amazon I've had a few sets from and the odd one or two from B&Q.
Paint
Rollers (Harris powercoat rollers are brilliant - I don't user anything else)
Small paint pot (£1 in B&Q)
Large 4/5" brush
Set of Smaller brushes
Roller tray
Old Tea Towels / rags
Sand paper of varying coarseness
Sugarsoap (for cleaning walls and ceilings prior to painting)
Wall scraper/stripping knife.
Coffee/Beer
Optional:
Mouse sander
1/4 or 1/2 Size Sander
Face mask
Goggles
Biggest floor fan you can get (see below)
That's more or less everything I used to paint my kitchen about 12-18months ago. HOWEVER, my kitchen walls were an absolute mess.. Cracking and flaking paint everywhere. And i mean EVERYWHERE.
So I used a stripping knife to scrape all the old flaky paint off first, then realized if I'd painted the walls as they then were it would be multi dimensional due to varying heights of numerous paints that were on the walls... So using the stripping knife I peeled off 90% of the paint from the walls. Surprisingly it came off rather easily. For the paint that had actually stuck to the plaster I used teh 1/4 and 1/2 sanders to sand the walls flat... This is where the fan comes in... Stick it near an outside door and it acts like an extractor fan. Sanding plaster is always going to be messy though (i taped up the door to the living room and there was still plaster dust covering the entire living room!!). I then sealed the plaster with watered down emulsion and kitchen paint over the top.
Still to this day it's as good as it was on the day we finished it. So in other words, its all in the prep
That's probably more info than you needed!