Ok, here's a pretty eclectic list, straight from my iPod:
Hotel California - Eagles
Sweet Home Alabama - Lynyrd Skynyrd
Anything by Jimmy Buffet or Bob Marley
Proud Mary - Credence Clearwater
Kingston Town - UB40
Red Red Wine - UB40
Summertime - DJ Jazzy Jeff
Vacation - the Go-Go's
Brown Eyed Girl - Van Morrison
Summer of '69 - Bryan Adams
More Than a Feeling - Boston
Tide is High - Blondie and others (Atomic Kitten is one I like)
Miami - Will Smith
Sittin' on the Dock of the Bay - Otis Redding
Soak Up the Sun - Sheryl Crow
Hot in Here - Nelly
What I Got - Sublime
Santeria - Sublime
Hangin' Around, Mr. Jones - ok, anything by Counting Crows!
When the Sun Goes Down - Kenny Chesney
Blister In the Sun - Violent Femmes
American Pie - Don Mclean - though Garth Brooks version rocks!
Hungry Like the Wolf - Duran Duran
Rio - Duran Duran
Free Fallin' - Tom Petty
Brown Girl in the Ring - Boney M.
Kokomo - Beach Boys
Pon de Replay - Rihanna
Amber - 311
Walk On the Ocean - Toad the Wet Sprocket
Fast Car - Tracey Chapman
You Can Call Me Al - Paul Simon
Drift Away - Uncle Kracker
La Tortura - Shakira
Hurts So Good - John Cougar Mellencamp
Jack and Diane - John Cougar Mellencamp