It's perfectly natural to want the best of everything for your wedding. However, if your parents are on a fixed income and you're not floating the bill, don't hold too steadfastly to a vision of crystal candelabras and $100 per-person plated dinners. This can put you well on your way to becoming a bridezilla.
You can have a great wedding without forcing your parents to take out a second mortgage. Just scale it back a little. So you'll have heavy hors d'oeuvres instead of a five-course meal. The guests can mingle in the buffet line.