I personally would prune it to knee height, but YMMV.
I planted several bareroot trees this winter and all of them got chopped to knee height. I did this because I followed the recommendation of Dave Wilson Nurseries (to be able to harvest without ladders). In my case 3 of those trees that are just single sticks about 30 inches tall are pushing new buds already. Here is the link to the video @ Dave Wilson nursery website.

Here is a link that might be useful: Planting and pruning a fruit tree - DWN video

I would prune the tree to as tall as you want the tree to be, if you cut off less you are only putting yourself back in the game. New leaves and growth will probably only come from the trunk if there are buds there. Otherwise you will probably get rootstock growth coming from below the graft.

This has been a much debated subject and always will be as there is no answer thats right for everyone. Keep in mind that there are lots of fruit picking tools you can use besides a ladder.

If it were my tree I would top it at 5' just below the current branches. In the Fall when it goes dormant you will have lots of possible scaffold branches to chose from.

fruit pickers.....

http://www.amazon.com/TwisterPicker-Fruit-Picker-the/dp/B000BBCUD8/ref=sr_1_1?ie=UTF8&s=hi&qid=1265849529&sr=8-1

http://www.amazon.com/Do-Best-M3-Fruit-Picker/dp/B000CZ4J6Y/ref=sr_1_2?ie=UTF8&s=hi&qid=1265849529&sr=8-2

I want my trees shorter and bushier so I am cutting all my bare root trees at about 2.5-3 ft range.

We just planted 9 trees this past weekend.

You have 2 choices, I figure. You can pull the 2 branches to horizontal and cut the top when it reaches your desired height and get fruit maybe a year sooner from a weird shaped tree. You can make those 2 branches your main frame even, if tree sends out no lower branches, which it probably would.

The other is to start the tree over as has been suggested here and shape the tree in the conventional manner. If the tree was just transplanted you may not lose time by doing this- unless the roots were undamaged in transplant (potted tree). Pears are one tree that I think may benefit from aggressive pruning after transplanting (with due respect to C. Whitcomb). They don't transplant well and dehydrate from root damage much more than most species. I have too often had pear trees runt out after transplant when they aren't cut back significantly.