The best investment I made (besides in my new husband!) were my eyelash extensions! I am one who usually doesn't wear a whole lot of make-up, but I was so excited for my eyelashes! I looked fabulous at all times - in the water and out. No mascara running, just naturally amazing at all times. Everyone was commenting on them the whole week of my wedding! I thought about keeping it a secret, but I had to tell everyone to try them out for themselves.
I got them in NYC at JJ Eyelashes http://jjeyelashes.com/. I had a Yelp coupon for 50% off. I got the longest ones you could get, and fanned them out at the edges. They did a great job. I highly recommend getting eyelash extensions instead of using prescriptions (Latisse), wearing fake ones just the day of, or wearing tons of mascara that may end up oozing down your face by the end of a swim or, worse, your wedding day!