I'm looking for spending around £300 - £500 on a nice watch.
I've been looking at so many watches and I need some advice on what will retain value.
Raymond Weil watches look nice, but drop in value quickly.
Does Tissot maintain value? Or what about an older Omega?
What do you guys think?

 

Neither Tissot nor Raymond Weil have very good resale value if you bought them new. The best of that class of modern ETA watches will probably be Hamilton although that's like saying they're the tallest midget at the circus.

Ashley / dsio's sugggestion about the Seamaster 36 is a good one. The non-chronometer 166.0xx versions (date or day/date) will be a couple hundred less than the chronometer 168.0xx models and are virtually identical. They have a modern enough look to stand up against anything today and the calibers to put some new movements to shame.

 

this one is a keeper...