All in about £450 worth of gear that will last..
My bodyarmour has been in the wash at least once a week for ...err... 8 years now...
Boots 8 years old..lost a clip last year but got one in the post for £3...
Gloves.. long trail rides wear under gloves to keep hands dry and keep blisters away..
Shin/knee pads again 8 years old..going strong..
Helmet..how much is your head worth? Get one with removeable lining that can be washed...
Goggles..best system is the strap off..especially in the rain or hot summer when no matter what type of lens you get it will mist up... one side clips onto the helmet and the other has a velcro patch so you can take them off from the side and dangle by the other..really really useful once you have tried them once...
Also look for a good pair of mountain bike spectacles.. Bloc are brilliant (6 years now) and come with four interchangeable lenses..give much better vision than goggles but don't protect the face from brambles/twigs etc... as much. Nice in the summer for a cool face...
Trousers and jacket... machine washable and breathable... no good staying dry in the rain yet totally sweaty inside...
Trousers must have lots of play.. over boot ones are very good but dont let the leg ends be too baggy or they catch on the pegs..
You can go cheap and replace them every two years or so... or pay a little more and keep them for twice as long....
Drinks system a must in the summer unless you want to stop for a drink... tool bag.. the moose system has lasted me 6 years and after a wsh looks like new still...(take the tools out first...)
Boots... MX boots are OK but most have smooth soles..no good at all for trail riding and you need idealy a walking boot pattern sole and they need to be flexable for walking distances in..MX riders dont usually walk very far...
If you dont mind waiting a week or so have a look at this US site... I got a lot of my stuff from here by mail order..brilliant for the larger gent as they have the right sizes...and they were CHEAP.. £35 for an 08 pair of moose overboot trousers, £10 per racing shirt, THOR KNEE braces/shin pads were £45...
http://www.motorcycle-superstore.com/ you might have to pay import tax when DHL deliver it but I've had several orders with no duty to pay..and if you do have to pay the tax it's not very much...and the UK price £80 trousers were still £35...