i have a intel i5 2400 atm, what would you suggest to go with for an upgrade
That will depend on how much you want to spend and replace. The lowest cost to performance upgrade would be a processor upgrade to an unlocked i5. Either the i5-2500K or the IB i5-3570k (with a BIOS update before swapping CPUs). Your i5-2400 isn't far behind the i5-2500K at stock, but the unlocked multiplier of the i5-2500k makes it easy to O/C it to higher performance.
Then you could consider selling the i5-2400 to lessen the $ impact.