Z series mobo and Corsair XMS3 or Kingston Genesis whatever is cheaper or on offer.
The Z series offers the overclocking features as well as having an IGP. How much you spend on the mobo will depend how bothered you are about SLI and or Crossfire.
Flick through the build threads you'll see plenty of i5s spec'd with Z mobos
lol or you could go for a budget but great board, and Corsair
Gigabyte Z68AP-D3 Intel Z68 £85
Corsair Vengeance Blue 8GB (2x4GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit (CMZ8GX3M2A1600C9B) [CMZ8GX3M2A1600C9B] £39
oh yeah, no interest in a 300 quid mobo.
My budget is around £100 for mobo. and really whatever is best for ram. I know that they shouldn't go above £60.
i was thinking of going up in budget a tad bit and getting this
http://www.overclockers.co.uk/showproduct.php?prodid=MB-493-AS&groupid=701&catid=5&subcat=1990
Is that best value for the price? (£145)
You can get 16Gb of Exceleram Rippler (2 sets of 2x4) for just under £50 and it's pretty decent. Unfortunately not from here, but worth having a look.
Motherboard wise the Gigabyte D3 is a great board for £85 if somewhat ugly.
Depends, you might get a slightly higher overclock and it supports SLi and dual 8x Crossfire. If you value those at £60 more then yeah, it's a decent board.
Sorry for such a vague original post but as one member pointed out you didnt set a budget.
The reason I said XMS3 and Kingston is that Overclockers use these parts themselves for the pre-overclocked bundles. Also they frequently feature on special offers, kingston genesis grey (2X4GB) is £40 currently.
As far as mobo's are concerned you need to ask what you want from it. If you want to dual card the GPU you'd be wise to pick a board which has sync'd pci-express lanes.
If you want to overclock the CPU an aftermarket cooler would be nice. Gelid tranquillo will be £20 odd if you bought the OEM i5K a heatsink purchase will be needed