I do have a 750 GB Hard drive on my laptop, but yeah, too many games, lol. I bought a laptop I knew had an expandable hard drive space for a SSD or whatever, but I haven't gone forward with said plan. With a laptop that's beginning to creep towards 2 years in age, I'm probably going to replace it soon enough, so I dunno about the upgrade. Though if I can just plug said new hard drive into whatever new machine I buy. My external hard drive is a finicky POS that disconnects whenever it feels like it. It's enough for backing up data like I want, but not an option for game, and not something that I necessarily want to spend a $100 to upgrade on.
I just keep unistalling old games as I get new ones, I already have like 550-80 GB dedicated to games, it's just that the new ones are getting so massive. I had to start uninstalling last fall to accomodate other space hogs like The Evil Within and Shadow of Mordor, and with all my new games since, I've wiped out somewhere between 300-350 GB of space for accommodation in these relatively few months.
I could fix all that by just investing in hard drive space as you said, which I might.