I've seen these threads a lot. There are a lot of options right now for 18650. None of them suck really. It comes down to preference and budget. The stand-outs in each category go something like this:
Versatility: GGTS
Thing is, for a dedicated 18650 mod, I'd pick something else. My GGTS is my dedicated 18350 mod. I love the small form factor and awesome looks with 1200mAH. It's not so handy with an 18650, but being able to use one with it has already saved my .... more than once. That being said, if my GGTS got stolen, I'd get another one immediately. They are the swiss army vape. If you can afford one just to have one, get one.
Versatility Different: Nuck Fistpack
The Nuck Fistpack *is* an 18650 mod. Nuck puts a booster circuit in the mod so you can wildly vary the output from 3.7v to high volts. It's a different mentality than the GGTS. Instead of swapping out batteries, you get a VERY compact 18650 unit that's amazingly comfortable in your hand, and you can slide the voltage where you want it with your thumb. I don't have one yet, but ask ANYONE that has gotten one how awesome they are. I keep trying to justify one, but I can't yet. Don't let that disuade you.
Size: The Precious from Romania.
It also has the nifty touch sensitive button.
Cool Factor: The woodicus maximus from nHaler.
While fat and boxy being based on a fancy cigar pipe material box (briar?), the height is perfect. There's also room inside. It fits your old cigarette pocket nice. And it just looks damn nice, and there's something about the vape. When people come over, that's the mod I get the most questions about.
Value/Cool Factor: The Chuck is pretty awesome.
There's no other mod you can get customized so completely. I'm not a huge fan of the switch, but I'm way in the minority there. It's solid as heck, heavy, and beautiful.
Overall Value: Silver Bullet
While not a huge fan of the Silver Bullet, you can not argue with the insane value they represent. They've also got a fantastic button, and a massive following. If you want "just works at a great price", it's hard to beat.
The mod I'm most interested in right now is the upcoming Super T Precise 18650 I ordered. if it's like any of the other SuperT devices, it's going to be absolutely perfect. There's a revolver manufacturer I love a great deal named Korth. I own several of their handguns, and I have them locked away. SuperT is the closest thing to a Korth the PV world has right now.
Now, ALLLLL that being said,
The mod I've been using lately is a 17670 mod. Only about 20 percent less mAH, will last all day, SIGNIFICANTLY slimmer than any current 18650 mod, solid stainless, and comes in at a great price-point. Due to the quality of construction and price, I'd put it at a better value than any current dedicated 18650 mod. It's the third version (v3) of the Puresmoker Prodigy pv. If I was recommending a first Low Resistance platform to someone that didn't already have a huge pile of 18650's, I'd recommend this mod.
The biggest thing to remember is (and this kinda sucks) nobody can tell you what you are going to like best. Case in point, there's this consensus that the woodicus maximus (I call it the TreeHaler) from nHaler is a horrible value because "It's just a cheap wooden box with a plastic button blah blah blah" but I've unintentionally sold two of them. It's the hands down favorite of the people that come over. People that tried everything else just love the thing. The *BEST* answer for all of these threads is always the same advice: Find out where your local vapers club meets. Attend a meeting. Talk to other people, and try the actual mods before you buy. There's no substitute for that.
Hope This Helps