Which watch for £300-£500?

[Salgar]

The OH is giving me some money towards a new watch for my 30th birthday. After reading a bit of this sub-forum it's safe to say I know nothing about watches.

I've been wearing the same £100 Swatch since my 18th birthday 12 years ago, and it's in pretty bad shape, and semi broken and not worth the money to fix.

I'm not sure what I want, something formalish (metal strap?) or something less formal. I'm probably going to end up wearing it for a very long time.

Also, does anyone know any good watch shops in London that will cater to this price range?

[Salgar]

Thanks everyone, so many good ideas here. It makes me want multiple watches... hmm...

Will update when I've finally made a decision.