If you lock frame to pole a theif can use the frame of the bike as leverage to pull twist or try to break your lock.
Lock the rear wheel inside the triange to a post, you cant get the rear wheel out, and the wheel is as hard to cut as the lock, actually a bit harder since it's under tension but if your concerned lock the seat tube or one of the rear triangle posts too. Locking the rear wheel to the triangle or seat tube is known as hobbleing the bike and makes the bike unrideable even if someone gets it off the post you lock to.

My favorite tecnique and one that's popular in the better books is known as cross locking. It's using 2 different locks. Using 2 different types of lock means a thief will have to have 2 different tools.

My favorite for weight, security and vesatility;
An Onguard Brute Mini U-lock and an Onguard Armored Cable/ Combination Lock.
I hobble the rear wheel or lock rear wheel to a post.
Then lock the front wheel and frame to post, or just to each other (to secure the wheel)
When i lock up for long or in an unsecure area I take the front wheel off and lock the post to the wheels through the triangle (securing both wheels) and then lock with the cable.
If you commute to work, buy a heavy chain and leave it there. Then use your regular locks as backups. If someone wants YOUR bike they'll jack it from work. If you have a big chain a cable and a ulock it'll take more than 10-15 minutes even with a mini grinder.
Overkill? Sure.