I have done both.
Just last week my DD challenged me with color selection. I wanted to make her a quilt to take on her choir trips - there is at least a trip a semester with her college groups. So I took her to our lqs to have her choose two or three colors. She came away with 5 - a dark teal, a teal print, a pink/purple/teal, a dark purple with tiny teal dots, and a bright orange - all these are batiks. She added - get this - an oriental print. It took fussy cutting and about 6 hours of coloring possible patterns to decide an original would work out best. But I knew if I picked the colors, it would not go with her. She would just leave it at home.
So - my advice - look at some of the available patterns. Get out your colored pencils, and see how the colors play together. Find one you like. Then go for it!
;)