my favourite is my park handlebar holder...keeps everything still during brake pad adjustments. go park! cheers, all

in descending order:
5: Greasegun
4: 10mm allen key for freehub removal -cos it's meaty.
3: Shimano cable cutters - like a knife through butter.
2: multiple allen key, screwdriver/ spanner thing that cost £2 and does 90% of the jobs on my bike.
1: Sachs Powerlink - no more bloody chaintools, bent links and a cleaner chain.

What I want: Track pump, workshop stand and a workshop instead of a corner of the kitchen.

Brant, how dare you slag adjustables? My dirt-cheap one does everything just about on my BMX (which I ride a lot), lets me loosen off awkward road signs (well, I am a student after all, what can I say), and the knives etc are fairly useful too. Obviously for the MTB a 5mm allen key as well as my big hefty 8 mil one with the padded handle for the crank bolts. And to whoever said track pumps, I agree, you will never want to use anything else once you have one.

On the subject - can anyone recommend decent cable cutters that are a bit cheaper than the Park ones (£20+)?

"decent cable cutters" and "cheap" don't work in the same sentence. i've wasted money trying. sacrifice twenty quid, it's cheaper in the long run.