Mobo+CPU Upgrade time

Hello,
So what I would like is to uprade my CPU+Motherboard.It needs to be Intel Core2Duo by the way.
Im looking at this mobo as I want to keep my GPU and memory just now.I was thinking I could still upgrade to a PCI GPU with this board later or a X1950 AGP,although I read that the PCI is only x4 instead of x16.Does any1 have a PCI GPU running on this board and if so is there a really big difference between the x4 and x16?

http://www.amazon.co.uk/MB775-V-PT88...5387773&sr=8-4

I dont really know what CPU to go for as I know this board isnt agreat overclocker wich is ok really cause Im not to sure about overclocking anyway.
So I have a few suggestions for myself,like these,

http://www.ebuyer.com/product/132064
or
http://www.ebuyer.com/product/121407
or
http://www.ebuyer.com/product/130486

I know people will say just to get a PCI motherboard only but I could also get a X1950 AGP card later on.Really im just looking for a significant boost from my current system.Having said all that if any1 has any suggestions to throw back at me I would be very gratefull.I am willing to spend about £150 or at a very maximum £200.Thanks alot.