If you need it now, an i5 2500k is awesome and you wouldn't feel bad about it. If you can wait for a few months, the i5 3570k will be amazing too. If you happen to have a CPU with an LGA 1155 socket already, you could upgrade everything else, then pick up the processor when it hits in April.
Most people won't notice the performance difference between the 2500k and the 3570k. However, if you plan on overclocking, the Ivy Bridge will probably be able to achive higher overclocks.
But really, unless you are going to SLI/Crossfire high end GPU's (which you don't appear to be), the 2500k is more than enough.
If you can wait, then definitely go for the 3570k (they aren't coming until April). Otherwise, stick with the 2500k.
will heres the link
Not Sure how my font got so small
http://www.newegg.com/Product/Product.aspx?Item=N82E16813131792
http://www.newegg.com/Product/Product.aspx?Item=N82E16814127560
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139010
http://www.newegg.com/Product/Product.aspx?Item=N82E16819115072
http://www.newegg.com/Product/Product.aspx?Item=N82E16820231314
http://www.newegg.com/Product/Product.aspx?Item=N82E16827135204
http://www.newegg.com/Product/Product.aspx?Item=N82E16835103099
http://www.cpu-world.com/CPUs/Core_i5/Intel-Core%20i5-3570K.html
But really, unless you are going to SLI/Crossfire high end GPU's (which you don't appear to be), the 2500k is more than enough.
If you can wait, then definitely go for the 3570k (they aren't coming until April). Otherwise, stick with the 2500k.
You won't regret it