Below is a basic grid I cobbled together you can use with any size website. You'll need to clear the floats on the columns with either overflow hidden or a clearfix. If your project doesn't need to support IE7 you can use box-sizing border-box to add padding to your columns, otherwise add an extra element inside each column for padding.
Whilst I can appreciate that making columns was super easy with tables that was pretty much the only thing they were better for layout wise.
HTML:
CSS:
.grid {
}
.grid .col { float: left; }
.grid .col.s1of1 { width: 100%; }
.grid .col.s1of2 { width: 50%; }
.grid .col.s1of3 { width: 33.33333333%; }
.grid .col.s2of3 { width: 66.66666666%; }
.grid .col.s1of4 { width: 25%; }
.grid .col.s3of4 { width: 75%; }
.grid .col.s1of5 { width: 20%; }
.grid .col.s2of5 { width: 40%; }
.grid .col.s3of5 { width: 60%; }
.grid .col.s4of5 { width: 80%; }