Hey bud, Welcome to VU. As you're new to vaping I can understand wanting to upgrade and wanting to try newer and bigger setups. If you plan on staying the sub ohm route, even just with tanks I would recommend looking at something like the Sigelei 150. It has a range of 10 to 150 watts and fires down to .1 ohms giving you all the versitility you'll ever need from a box and keeping your MVP as a backup.
But to power a mod like that you're going to need good batteries with a continuous amp drain rating of 20 amps or more and a good battery charger to charge them with such as any Xtar brand charger or one from the Efest LUC series. For batteries I recommend LG HD2 or HB6 or Sony VTC 3's or VTC 4s. Despite the low 1600 mah rating of the VTC 3's I get about the same amount of run time from them as I do my LG HD2 batteries which are 2000 mah. I will link a couple threads below to give you the basic in's and out's of things and if you have a brick and mortar shop close by you can go look at stuff and hold in your hand i highly recommend so...even if you plan to shop online it's always nice to get a literal feel for things. Best of luck on your hunt for a new mod and happy vaping. Oh yeah,...I am adding an ohm's law calculator as well...if you're going to sub ohm, prebuild coils or self built, you need to have a basic understanding of ohm's law...see linked threads for more details.
http://thelocust.net/ohm/ ------ ohm's law calculator
http://vapingunderground.com/threads/new-sort-of-to-vaping-and-want-huge-clouds.57203/#post-342138 ----instructions and helpful shopping hints and info
http://vapingunderground.com/thread...-sick-clouds-bro-thread-sticky-edition.78126/ ---Vaping Underground's unoffical "how to" beginners guide to advanced vaping penned by one of our mods and a heck of a nice guy
@OBDave