I5 3570K OR i7 2600K

i7-2600k Should be faster. Since it is used just make sure that the i7-2600k works well.

i5 3570k is decent choice for both.

so 2600k over the 3570k?

and the 2600k is even 30$ cheaper

one question which stuff are you going to do much, GAMING or PHOTOSHOP?
basically both are chip are same in features but 3570k even has features over the 2600k?

gaming

For gaming if the prices are the same I would go with the 3570k, but since the 2600k is $30 cheaper, I will go (personally) with the 2600k. Like I said before make sure the 2600k is in a good condition. For photoshop and other non-gaming programs 2600k should be an easy choice.

then sure, grab an i5 3570k it is even ultimate choice for gaming.

OK i ll grab the i5 and since the i7 was used its the best option

i7 and i5 are basically same chip's but i7 has only hyper-threading which is useless in games.