I bought my husbands ring at the same store where he bought my ring. We were actually shopping together, and we had already had the conversation and found the perfect ring for me and was less than he was hoping to spend. I still love it even 15 years later. Anyway, we found a mans ring that is "complimentary" and somewhat similar to my ring. Also, there was a bit of assurance that the diamonds were decent.
He had actually been married before and was expecting to get another standard gold band, but I insisted that he get something extra special because he would wear it until he died, and he will (or I'll kill him.)
My suggestion: Don't go crazy on the budget, but get the nicest thing you can afford because it's permanent.