I was strongly considerin' gettin' a hard drive, but one vastly important thing came t' mind 'fore the purchase: I loves me some used games. I'm sure certain old titles on the eShop will become cheaper as time goes on, they'd have to in order t' compete with the used game market, but I'm also quite sure used games will still end up bein' cheaper.
... Another problem is I'm always short on cash. If I bought a decently sized HDD, I wouldn't be buyin' any games for another few months. So no, I didn't get any external storage. Disks only as of now.