I read recently that it's important not to get an oil past its smoke point, and well, my mother has a LOT of extra virgin olive oil so that's about all I can cook with. But it appears to have a smoke point of 375 F, and I typically oven roast at 450. I'm thinking of trying oven roasting at 350 instead, but would this possibly adversely affect the vegetables (as in, make them less crispy and mushy instead)? I'm just trying to be as healthy as possible here! =D

The temperature of your oven isn't necessarily the temperature your food will get to. Think of a roast chicken - when you put that chicken into a 375 degree oven, you're not trying to get the temperature of the chicken to 375 degrees - you want to slowly raise the temperature of the chicken up to above 165. Food in an oven does not get to the temperature of the oven, because the heat is ambient and not directly under the food.

You run into smoke point issues more with frying (where you have a high heat source underneath your oil) and other situations where the oil is on the stovetop.

I roast at 450 all the time with olive oil - I doubt the oil gets anywhere near that temperature while in the oven.

I fry with EVOO too and it does just fine. The only time it is really an issue is with deep frying and who needs to do that? When I make my omelets I heat the pan, add the veggies and THEN add the oil to the food and stirfry and there is never a smoke point issue.