Maybe Mrs P will buy you a bike for your birthday! ;-)
Or else get it serviced at your local dealer - they are usually pleasantly surprised when a bike comes in with lots of wear in it!
A few thousand miles is nothing!, with regular minor maintenance a chain should last about 2500 miles and everything else should last tens of thousands of miles.
Of course if you want a new bike anyway. Then go for it.
Gaz, you are an optimist!
My experience of year round, all weather commuting on grimy urban streets, is that 10,000km does a lot of damage to a bike. I would have to have changed headset, bottom bracket, wheels (if using rim brakes), multiple chains and a few gear cassettes.
I agree with Jon, a good local dealer could make it feel much better.
Not sure what tarmac cycling does to brakes, but the cycle paths in Deeside are finished with granite dust which wreaks havoc on brake blocks... (though on a positive note it does reduces the caked-on mud).