Congrats on quitting smoking!!
It sounds like you're ready for a mod? There are many out there to choose from. Most of them are pretty large, in order to hold the larger longer batteries.
The Precise+ in 18350 size is dainty, super well made, (top craftsmanship!!), has a special berium connection that gives a harder hit than most 510 mechanical mods, and if you have enough spare batteries on hand to charge in a nice Xtar charger, you'll get along swell. They're at Super T Manufacturing http://www.supertmanufacturing.com/ They also sell for top dollar if you decide to sell it and get a different one.
Another,nice one is the Piccolo, but they're a little harder to find. Long and slender.
The eGo-Twist is a wonderful battery! It's the size of an ink pen, yet it's variable volt! They're very affordable, and the main stay for newbies and Veterans alike. I would go with the Twist while researching other mods.