It really depends on the game you play and the game you want to host. 'Game' is ambiguous in the previous statement.
The Game you play: PLO is going to play larger than NLH, and it gets there faster.
The Game you want to host: Fast action, high or low stakes, caps on buy-ins.
I also think resale should play into it; you're not going to own the chips forever, even if you clutch them in your dying breath. I wouldn't spread 120 fracs per se, but I will sell 3 barrels to a Frac-hor (and I have, previously ousted player above in the thread), and I respect the next host that may own my chips next.
I bought a set with 60 fracs (CPC, it was my order), and it's always been enough for my game, but not everyone enjoys the action in my game. We've started with .25/.25 and have since moved the game up to .5/.5, but we typically felt 1500-3000 on the table.
Having a few too many fracs on the table isn't a big deal, but I've played in a game where everyone gets a rack of fracs, and it slows the game to crawl; it really isn't any fun to deal with.
If you have a bunch of nits, sure, have a frac-only game, but if you have stacks going in, you don't want 2 racks on the table. If I ask how many racks of fracs you have on the table, it's because I'm baselining your nit-to-player ratio.