Suppose that you could grow any fruit or vegetable regardless of your climate. Well, regardless in the sense of tomatoes in Alaska – if it has a definite season, you’d be limited to its season, not get watermelon 12 months a year.
If you could, what would you have growing out in your backyard?
Me – I’d have a nice big avocado tree.
Capsciums
By which, of course, I meant capsicums.
nectarines
or mandarin oranges
but in live in Zone 3 (bordering on Zone 2) 
See Cuncator’s answer.
Or maybe coconuts…
Raspberries. I’m all about the raspberries.
Assuming I could eliminate the %#@)?! groundhogs that inhabit my neighbor’s yard but come to mine for the buffet…
I’d go for an avocado tree, too. And artichokes.
mangoes
wine grapes. Either zinfandel or cab sauv, or both just for the heck of it.
Asparagus. And artichokes. And papaya. I had a papaya tree in Hawaii and it was so yummy.
Corn. There is nothing better than fresh corn on the cob.
Can’t grow it because I’m in an apartment now, but:
Tomatoes.
And blackberries and raspberries.
I agree with Malienation and Fritz. It’s all about the raspberries.
Mmmmm…raspberries… drools
My parents used to have black raspberry bushes in their backyard, and my grandparents had red raspberry bushes. We used to pick them and eat them right off the bushes (watch out for the brambles, though!). And my grandmother made the most heavenly raspberry torte.
Strawberries. Or bananas. Or, since we’re wishing, a strawberry-banana hybrid. 
Opium poppies! Er…opium counts as a vegatable right?
Ok if I can’t have that, mulberries. I grew up with a mulberry bush in my front yard. Now I find it’s practicaly impossible to get one if you don’t alreadly have one. You can’t buy them. I would love a mulberry bush.
Mangos, yes. St. Julie/ East Indian hybrid mangos.
Does the mojo that lets me grow whatever include a reduction in the PITA factor for preparation? 'Cuz I love field peas, black eyed peas, purple hulled peas, and butterbeans, but absolutley hate to de-pod them. Hate it so bad I’m blanking on the word for the process.
New Mexico chile and tomatoes.
You can’t grow raspberries in Maryland or California? I figured they grew everywhere. We’ve got lots of wild raspberries where I grew up.
I’d go with avocados or oranges. Or maybe pineapples - I don’t like them quite as well as the other two but I’ve heard they taste really great fresh off the vine.
Oranges. The climate here in the UK, even where I live on the south coast, is just a tiny bit too cold and wet for citrus. Of course they can be grown in tubs and moved under glass for the winter, but I’ve tried that and it’s difficult, and it doesn’t really work.
So I would dearly love to be able to wander into my garden and smell orange blossom, or pick a fresh orange straight from the tree. I spent a few days in Spain back in April - which is actually a little late for the main orange season, but the trees were in full flower and there were still oranges to be had, just not so many of them.