Most places in Northampton are either overrated or mediocre at best. Circa is good but not great and spollettos is extremely overpriced and mediocre. From what I hear the best places are within a half hour's drive:
Chez Albert in Amherst
Circa's isnt bad. We were just there tonight but it was a bit dissapointing. Stay away from spoletto's/del raye's. Green STreet is supposed to be good and Viva's is a very affordable nice pasta place. The thai place is decent. I want to check out apollo grill. I have heard good things about it.
I'm not sure what you feel is expensive but here's some decent choices for a date. I'll stay away from recommending small hole-in-the-wall ethinc joints, but if you want to know about some just reply.
Spoletto is reliable italian/American (my girlfriend took me there on our first date -- now we're married). My wife likes Pizzaria Paradiso - it's pleasant, not expensive. India House on State St. is good. The best joint in town is Del Ray but it's more pricey.
Stay away from Northhampton Brewery and Smokin' Lil's. Yucko on both.
If you're willing to drive 10 minutes out of town, I'm a big fan of Apollo Grill in Easthampton: http://www.apollo-grill.com/
We were there recently for an evening after several years. A friend recommended Circa. Prices are not low, the food was more than good, in some instances excellent (particularly the wild mushroom soup). The service was faintly ridiculous, a whole lot of staff who in their collective effort never manage to achieve the goal. It was a pretty good dinner and the setting is nice, maybe our impressions were affected by the memory of a restaurant called Lady Bird's, which used to be in the same spot and was perfect in every way.