Intel 2500-k for gaming

Absolutely YES to all of your questions and this would be a good board, IMO http://www.newegg.com/Product/Product.aspx?Item=N82E168... or if you want to spend a bit more http://www.newegg.com/Product/Product.aspx?Item=N82E168...

The i5 2500k is one of the best, if not the best, gaming CPU available in the market, Yes it can be Overclocked (very)easily.
+1 to the above motherboard or
ASRock Z68 PRO3 GEN3
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
ASRock Z68 Extreme3 Gen3
http://www.newegg.com/Product/Product.aspx?Item=N82E168...

yes.

yes. you should consult overclocking section for more information and consult the oc guides there.

yes, plenty. core i5 2500k has unlocked multiplier which enables capable users to raise multi ratio and raise the cpu clockrate.

depends on your budget. you should consult the motherboard section for better info. if you're building a whole pc, skip individual section (except overclocking) and ask in the systems section for help with overall build.
as for motherboards, i5 2500k will benefit from motherboards which allow cpu overclocking (e.d. z68, z75, z77 etc.) and has good power delivery system, component layout, fan headers etc.

Thanks guys

My personal favorite motherboard for the 2500K would be the Asus Maximus IV Gene-Z. Its $190 at Newegg right now with a 10% off coupon so $181 shipped. Cant beat that.

Guru 3D did a review on it a while back and said it would overclock their i7-2600K further than on any motherboard theyd tested to date. Thats pretty solid.

The only downside is that since its mATX form factor, its only got 2 PCIe slots so while you can still run dual video cards, you can run dual GPU's and a sound card. Not that that should be a big problem because it has a very good sound card on it already.

For price to performance the 2500k is probably the best CPU out there. Also yes the I5 can be easily overclocked with good aftermarket cooler you can easily hit 4.5 GHz.

Best inexpensive, when compared to the performance you get, CPU on the market. It also overclocks like a champ. Just buy it. If you're looking for some good budget boards, AsRock makes some great Z68 boards that overclock well.