depends...
Now if you can get a X2 cheap, then yes. most of them can run 2.6 stable with almost stock voltage.
Now if you have to buy it NEW... NO...
Your better off with an opty 165. Your gaurentee'd a 2.6ghz minimum or higher oc. I havetn seen 1 165 that couldnt do at least 2.6.
If you have a little more money to burn, id find a opty 175. Thats where the sweet spot for price/performance ratio ends. Also. you'll love the 11x multi