consider heritage pears
http://denmylne.wordpress.com/about/http://denmylne.wordpress.com/category/sources/also consider the local orchard groups near where you live, always a good source of information, there are loads of community orchards right across the uk, with amateurs who prune them, ask if you can help.
When considering varieties, the following should be taken into account.
1. what time the fruit is ready, eg if you plant concord, bon chretian or conference, these pears all flower and bear fruit at roughly the same time. not only giving a glut of fruit, but also succeptible to all being wiped out by a hard frost during the blooming period. a mixture of early and late fruits which flower and fruit at different times helps to avoid this. see the crawford, lindores, glasgow yelllow and craigs favourite.
2. when planting new orchards, consider planting family trees, ie a tree with 3 or more types of apple or pear types grafted onto the same rootstock, you can then decide at a later date, which ones to keep and which ones to prune away.
3. be aware that it is the rootstock that is the most important part of your trees, some of the pear trees in Newburgh are grafted onto rootstock planted in the 12-1300's and the trees them selves are perhaps the 3rd or 4th types to be grafted onto the same rootsock. you can see an example of a rootstock being regrafted in the link i gave you above. Think about how well a small graft, essentially nothing more than a small twig, will do on a 10 year old rootstock than say on a one year old
4. North, East, South or west.........some varieties can only be grown on a south facing etc, this is why family trees are a good idea, some trees will do better in one location of your field and others of the same type not as well in the same field.
5. Someone mentioned size in one of the posts above. this is a function of the rootstock and a serious consideration. just remember that any "variety" can be changed by simply grafting a different type onto the tree, eg, quince is used as a reducing rootstock for pears,onto which is grafted an interstock, usually doyenne de comice, followed by what ever pear type is required, eg conference. if you alow branches to grow from the quince part of the tree it will bear quince, the comice, comice pears, it is normal practice to trim these branches and to only leave the concord. Consider a few full standards but remember, a dwarfed tree which is shaded by 2 full standad trees will not thrive, so consider the direction of the sun and tie this in with your rootstock, ie dwarf to the front, half standards and then full standards to the back
6. Think about the long term nature of a fruit tree, when planting, dig as big a hole as you can and fill it with the best compost you can find. in times gone by they would throw in a dead sheep for good measure. You are effectively feeding it for the next 50 years.
7. Remember that the term pruning covers a lot of different operations, one of which is shaping. The shaping of the tree in the 1st 5 years is the most important, after which, depending on the vartiety will, they can be left to their own devices. eg, a tree which is grown in a straight or balanced manner will thrive, a tree which is growing at at steep angle will eventually topple over and die.
8. Lastly, use proper round stakes and proper ties. consider very carefully how you will protect the trees from rabbits and especially voles, I had 2x 50 year old bramleys wiped out in 24 hrs by rabbits. I have also seen several 100 5 year old james greives being ringed and killed by rabbits over a period of 2 weeks.