My 2006 Marzocchi AM SL1s have gone a bit stictiony, wobbly and annoying despite being serviced recently. So I might replace the bushes, keep them for spares and get another pair of forks.

So what's out there at the moment for reasonable wonga?

Must haves:

Reliable
150mm travel
Adjustable travel down to 120 / 130mm or so.
Air fork (I want tuneability and I can't be bothered arseing around buying new springs)
Bolt through (20mm if poss)
As light is possible
Take a 200mm rotor
Plush

So far I've been looking at the following, which can be had for ~£550

Magura Wotan (look to tick all the boxes other than being heavy)
Magura Thor (light but a bit short on travel. Not sure how to fit a 200mm rotor?)
Rockshox revelation team air u-turn (look bob-on)

Any opinions?

Any others in this price range i should be looking at?

This has probably been asked many times before, but I'm going to ask again anyway!

Rock Shox Sektor

you mentioned the 140mm Thor so:
http://www.jejamescycles.co.uk/fox-32-talas-rlc-forks-titanium-id56353.html#info at 15mm

Depends what bike it's for, but if the Rev is beefy enough then I'd go for that.

Not what most people would call cheapish though!

New Rockshox Sektor when it comes out?

http://www.dropmachine.com/News/sektor-the-new-bull-dog-in-the-150mm-travel-arena-a602.html