So much depends on your climate. I wanted variety so we have:
On walls: Figs, apricots and peaches (peaches have had a great season, figs are grabbed by the wasps as soon as they ripen but are amazing)
Sheltered positions: Almond, persimmon
Then in various orchards or open areas cherries (sweet and sour), gages, plums and damsons (could also go with bullaces), apples (probably about 25 varieties), pears (4 varieties), quince, mulberry, medlar (only used for jelly really but can be kept), walnut (patience required), sweet chestnut (ditto) and hazelnuts
Soft fruit: Raspberries of various varieties, blackcurrants, white currants, pink currant (not convinced by that - lots of top growth, not much fruit), red currant and a couple of gooseberries
We've also planted 2 acres of vineyard which will start to fruit in two years time (or rather will be allowed to fruit) - that's a longer term project - as well as three vines for eating grapes.
The main reason we went for so many apple trees was because we drink a lot of fruit juice so we've got the crusher, press and pasteuriser so we can produce loads of apple juice which lasts for ages once pasteurised. If you are going to try and keep apples for eating throughout the year, you need to pick your varieties carefully so they store as long as possible along with some that are read to eat early. Otherwise you could end up with a glut of apples that have all gone wrinkly by March and you end up with a six month window of nothing decent to eat.
We are also very lucky to have a warm site so the peaches and apricots can blossom early and ripen in time (peaches in particular which we're eating now - apricots can cope with a shorter season but do blossom very early).
You also have to consider predators. We have planted 15 cherry trees but have yet to get more than the odd cherry because the birds have them all early - and this year pigeons stripped all the early leaves from the middle of the trees too which knocked them all back. So you might need to net trees and soft fruit. We're in Kent and virtually all the commercial crops are now grown under cover - all the amazing Kent cherries are from glass houses, polytunnels or at the very least netted. Apples are easier to protect but I did notice that a lot of ours have been attacked by birds already which then lets the wasps in.
Most of our trees were planted the first winter we moved here so 2 1/2 years ago - the soft fruit kicks off quickly but this is our first year with a few decent apples on each tree and the walnut, sweet chestnut, persimmon, mulberry, quince and most of the gage/plum types things are yet to produce anything. In the case of the plums I think that was weather related but the rest take five years plus to fruit.
If you can find a local nursery with a good variety of fruit, that helps. I've bought from two local places here - mostly Keepers in Maidstone who have a huge variety of all fruits and will advise on any area of the UK but clearly know this area well and Victoriana which are just up the road from here but have a more limited range (but had some apple varieties Keepers didn't do - along with the almond tree which is doing surprisingly well).
H