Altura Dryline trousers. Look like lightweight freeride pants, don't get in the way of pedalling, keep water and filth off. Not even expensive. Absolutely bloody marvellous.
I haven't got the money to get myself some tights at the moment, but I reckon that if it's cold and nasty enough to need them, no one will be out to see you anyway ;-)
Actually they're slightly more expensive than I thought they were (£69.99) but they're reinforced and I've been crashing regularly in them without any rips or tears. There's a full review on the site too, I'll be back in a minute with the URL.