Intel hasn't finished IGP CPU spec
We're already seeing a lot of motherboards from CeBIT based on the upcoming Intel P55 chipset for the LGA-1156 processors which might or might not be known as Core i5, but it seems like there's a fly in the ointment, at least on the boards that feature display outputs.
As the P55 chipset is the first chipset to launch for LGA-1156 processors, our understanding is that Intel hasn't quite finished some of the spec's for its CPUs with integrated graphics and as such it's not certain that the P55 chipset will support these processors or not.
For the consumer this isn't a huge issue right now, just stay away from any P55 motherboards that has display connectors on them, as they won't work with the first generation of CPUs, as these CPUs don't have integrated graphics. As for the motherboard manufacturers, well, time will tell, but the current designs might not work once the CPUs with IGP becomes available in early 2010.
The H57 and H55 are sure bets to work with the CPUs that have integrated graphics as they will be designed for the new CPUs. This might cause a lot of confusion for some consumers and the upgrade paths are anything but clear. For now it seems like you might have to swap your board every time you buy a new CPU, which will make upgrading more costly than it has been recently. Then again, a lot of people just buy a new system these days, so maybe this isn't a huge issue for most.