H61 series is designed to be an entry level board chipset and will not allow many of the performance features + integrated graphic
P67 & H67, they are just 2 slightly different chipsets for different user segments. Intel's graphics core is integrated onto the CPU chip itself (hence the meaning "die").
P67 does not support integrated graphics ussualy or overclock
All three chipsets are very similar (especially the H67 and P67). Here are what I consider to be the main differences.
H61: No overclocking, No support for SATAIII (6.0 Gbit/s)
H67: No overclocking (some would say very limited), 1333MHz memory limit, can utilize on-die graphics
P67: No integrated graphics, can not utilize on-die graphics
Basically if you are thinking of purchasing one of these boards, then you need to ask yourself what you are going to be doing with that build. For example, if overclocking is your thing, then you definitely want to go with the P67. If you want something basic, then go with the H61. If you want a nicer HTPC and don't intend to overclock, then you probably want to go with the H67.
Not sure what you mean exactly by "ok", but they are compatible, so yes it is ok to put an i5-2500k on a motherboard with an H67 chipset.
Some people might consider it a waste to by an unlocked CPU (k) and put it on a motherboard with a chipset that doesn't allow for much overclocking, but the i5-2500k is only $10 more than the i5-2500 so it might be worth the extra $10 because you never know if you will end up with another motherboard in the future.
Also, even though most people who would buy the 2500k would also buy a video card (and not use the on-die graphics), the 2500k has Intel HD 3000 graphics, while the 2500 has HD 2000 graphics.
i purpose to buy intel i5 2500k but not intent to overclock, that why i take a look for motherboard H67. So, is it still OK for gaming? We know that overclock will increase CPU tempreture, so i just like normal CPU tempreture with high perfomance..you think 2500 or 2500k is better for my situation?