I like
Fuego, in downtown Arlington Heights, for upscale creative Mexican food. I realize that opinion on Fuego is mixed, but it's geographically convenient for you, the atmosphere is pleasant, and I think the food is reasonably good. As another option, for Mexican seafood,
Flamingo's, right next door in Mount Prospect, is also excellent and worth considering.
I also like
AltThai, in downtown AH and recommended above, for Thai food. The contemporary decor makes it seem more trendy than your typical Thai storefront.
Another possibility is
Yanni's, a nice Greek restaurant in AH, right off the Tollway at Arlington Heights Road and Algonquin.
It may also help to review this discussion about dining options in downtown Arlington Heights:
Downtown Arlington Heights?