HI, I am planning to go to nepal next year summer. My F1 visa expires on June 10 2012. However I will still have 3 years to go in my college so wont be out of status. And I am planning to get back a couple of days before my visa expires. Has anyone had this experience of coming back just before the visa expired. How much time, before the visa expires, do you think I should be back? Please share your experience. Thank you very much... 

One of my friend whose visa would expire in 3 weeks re-entered US  without any problems. Even if you have atleast one day valid visa while you are at the port of entry, you will be allowed to enter US. 

However, your passport should not expire within six months. You should have valid I-20 signed on the third page  by International Student Advisor or someone of similar post at your University, the signature should not be older than one year during your return. 
I hope this helps!

yes you are right technically