If you're looking for a happy medium, take a look at this J.Crew Sweater Dress. While the price is very reasonable, this piece is an easy wardrobe update. You can also take a look at this J.Crew Evening Dress. It's an attractive option both price and quality-wise.
If you're willing to splurge, then you absolutely must check out this J.Crew Shirtdress. This product seems expensive, but it's worth it. Why not take a look at these J.Crew Dress too? Expensive, but worth every penny.