Right now, there are quite a few:
5) The Squiffer, specifically New Squiffer. The fast charging makes it the easiest Charger for me to use (though I like to play aggressively, which doesn't always gel with Charger use), and Ink Mine/Inkzooka lets me cover all ranges with this weapon. The Classic is pretty nice too though, can't complain about Bubbler.
4) The .52 Gal, specifically Deco. I love the power and range, but what makes it great for me is the Seeker/Inkstrike loadout; Seekers are great for getting around and attacking beyond your range, and Inkstrikes are just great generally.
3) The Splat Roller, a very well-rounded and powerful weapon. Suction Bombs and Killer Wails let me attack at range, while close-up foes get whacked with the roller.
2) The L3 Nozzlenose, the one I didn't expect to enjoy. It's quite good for turf coverage with its burst-fire, and it has Disruptors to ensure that ambushes go smoothly, plus Killer Wails for area denial and attacking through cover. A very good weapon, even with its quirks (it's really more like a Blaster than anything, it even shares the same loadout).
1) The N-Zap '89, my favorite currently-released weapon. It's very well-rounded, but Sprinkler gets me frequent Inkstrikes when I can stay alive. It's one of the few weapons with which I don't feel like my team has to carry me (2, 3 and 4 are also this, 5 a bit less so), which is something.