Here are some of the tools not already mentioned that you will probably want;
Blow torch- I recomend the rothenberger superfire2, +fire extinguisher (powder type), plus flux, solder(lead free), gas (map gas prefarably) and a flux brush.
Small mirror- either an extendable one or simply a little make up mirror. Very useful little thing to have in the toolbag.
Camera!- the one on a phone is fine (I like to take before and after shots but maybe thats just me^^) also good if you look at a job but wont be returning for a while to do it, much quicker than making a diagram. Calculator on the phone can be useful too.
Box spanners for taps (monoblock and regular) and an adjustable spanner, like this one- although not this one as it looks cheep and nasty but you see what I mean: Adjustable Basin Wrench - NoLinkingToThis, Where the Trade Buys
Having these makes life a lot easier when access is difficult.
I love my multitool! - pliers/wirecutters, knifes, saw, file, screwdrivers, alan keys, and various other random spikey bits all on your belt- best bday present I ever got!
Stop ends(2x15&22 min.)
Rad key and rad bleeding key.
Mastic gun, floorboard saw, emery strips/wirewool, round and flat files, garden hose and hose clips, scraper (the sort with replacable blades), wd40 or similar, tubs for catching water and a towel for mopping it up, gloves (disposable and riger type), safety goggles, ear defenders, stubby screw drivers. Toilet/kitchen roll for testing for any weeping joints. Dust sheets and dustpan and brush.
Stud/metal detector, multimeter, approved voltage meter, temp. earth bonding clamps (jump leads will do).
Steps/ladders.
Then later when you have more money: Pipe bender, Drills (combi and sds and bits- masonry, wood, holesaws), jigsaw, circ saw, angle grinder (I have 2 a standard makita one and a dremal for tight spots, both with diamond blades).
Hope that's of some use, you wont need it all at once though so like someone already said get what you need for the jobs you have to start out.
