worth upgrading skt939 cpu to dual core?

I've been considering if I should switch over to Dual core, but not sure if I'll get my moneys worth.

Im on a 3700+ which seems to be coping well on things at the moment (Gaming and DVDs mainly).

It is running at stock and overclocking could be an option although it's something I have no experience in and not sure my other parts are up to the standard.

Anyway, I was looking around and have seen some different dual core options.

4200x2 for around £80 (new oem)
Opteron 170 for around £85 (new retail)
keeping an eye out for 4400x2 for around £80 (2nd)
4800x2 for £95 (2nd)
3800x2 for £65 from ebuyer

what do you reckon?

Its not a great value upgrade but its the last chance to upgrade your present system.
If you are not planning a new system in the next couple of years then go for it.
I would get the 4200 from Scan.

Same situation here. I would rather put the £80 towards a budget 965 mainboard £60 and 1GB value DDR2 £20. OK I need to spend another £70-£100 for a C2D CPU but I would not be happy with Dual 939 for very long. For starters hardly any games are multi-threaded. Only possible reason is to compressing video quicker and to play supreme commander. Not much reason if you ask me. Stick with the 3700+ and relax. Relax some more by ignoring windows Vista. Life is good.

Went from a 3700+ to a Q6600 last month and I can't belive the difference it has made :D Still have the same gfx card but it's even noticeable in games and my 3dmark05 result was up by about 35%.