Restaurant.com certificates are 80% off again, making the $25-off coupons just $2 and the $10-off coupons about $0.80. Use promo code LOVE through 2/14 to get the discount at checkout. (If you're not familiar with how this works, read this.)
In case you were planning to impress your thrifty valentine with your coupon savvy, though, please remember to check with the restaurant first to ensure that they'll accept the certificate on holidays. I got burned this way with a Restaurant.com certificate, even though there was nothing in the fine print about blackout dates, so call ahead to confirm.