I'm looking for a reasonably priced crisp white and rich red for a summer wedding. People in their 20s seem to like pinot grigios while people in my age group tend to gravitate to chardonnays, so that's my dilemma. The menu is a choice of chicken, fish or vegetarian.
Let me start with a contrarian opinion, if I may: The menu should not be allowed to factor heavily into this decision.
You've got to satisfy a large crowd, and I suspect most people won't pay much attention to the suitability of the wines with the food. People tend to judge wine on the first sip. If they like it on its own, they'll generally be happy with how it pairs with the food. Not everyone, of course, but I'm speaking in broad terms. (Dinner parties at home present a different scenario. Guests tend to be more focused on what you've lovingly set out on the table and may be more disposed to cut the wine some slack if they are given the impression that it was chosen for the meal.)
Besides, you've got several food options for the wedding, none of them very heavy. Depending on how the dishes are prepared, you may not want to go with a rich red at all, assuming food-and-wine matching is your paramount concern. For delicate fish, for example, a light, crisp Beaujolais would be more suitable than a hefty cabernet sauvignon or shiraz. But the vast majority of guests will not, I guarantee you, love Beaujolais regardless of its synergy with fish.
Putting aside the matter of food, I think your instincts are sound with regard to the wine guidelines you've set for me. Pinot grigio is immensely popular; it will please many people (though perhaps not most wine critics!). So is chardonnay. And most people who drink red in Canada favour big, mouth-filling wines (not Beaujolais).
Given that cost is a concern, as it is with pretty much all weddings except those of the royal kind, I'd be more inclined toward crisp pinot grigio than chardonnay. It's a summer wedding after all, and light, zesty wines tend to taste better in the heat. More importantly, you'd be hard-pressed to find a good chardonnay for under $10.
Citra, a big, widely available brand from Italy, makes a decent pinot grigio for $8.25 (in Ontario), though there are many other bargain options.
If you're willing to pay more, I'd suggest Masi Masianco from Italy ($15). It's based mainly on pinot grigio but contains a dollop of superripe verduzzo, which pulls the wine into richer territory that may also please a chardonnay lover. Another option, at about $16, is Anselmi San Vincenzo. It's mainly based on the zesty garganega grape (not dissimilar to pinot grigio) but it contains a small quantity of chardonnay – again, giving the wine more heft.
As for rich reds, Chile offers great value. At about $10, Cono Sur Bicicleta Merlot is a bargain, substantial yet crisp. Even better, at about $13, there's Pasqua Villa Borghetti Passimento. It's a dynamite value from northern Italy, a turbocharged Valpolicella made from grapes that were left to dry for a month after harvest to concentrate flavours. Wines from Italy made in this manner have become very popular. You can think of them as rich-red counterparts to light, fashionable pinot grigios.