Get the best you can afford mate.
Front is relatively easy either way, a set of springs matched to your weight and riding style and oil to match should sort that out nicely. On the rear, I'd personally not buy a Hagon as they don't have seperate compression and rebound damping - that said it's still a very good shock, just the adjustment is limited. Depends entirely on how much adjustment you want really!
Buying new, I think I'd have to go for a Nitron Track (seperate rebound, compression, preload and height adjustment), as that'd do everything you needed unless you started racing basically. Second hand might be an idea, could try keeping an eye out for a used Ohlins to pop up on ebay, even if it needed servicing and resprining it'd add about £150 odd, so might be cheaper that way.
Other brand that might be worth a nose is a German one called "Wilburs", they're also very, very good, and are slightly cheaper than Nitron for the same specced shocks I believe - that said I've had personal experience with Nitron and they are top class in terms of their custom service!
I've also had WP on my last bike, and it was fab once set up - in all honesty though I don't think I'd be able to tell the difference between a well set up Nitron, Ohlins or WP so it's more a case of get what you can