Some random thoughts:
So you've never used cartomizers, then? They are a good, reliable way to vape. Some, especially devout drippers, find their flavor lacking (muted or changed). If you come from the cart-atty setup, then cartos are definitely an upgrade, but if you come from dripping... meh...
DCTs are extremely popular, but I am not very sure they are the best way to go with carto-tanks. First, as the name suggests, they are made for dual-coils, and these cartomizers do not perform incredibly well at low voltages. You can fit single coil long cartos, such as the Smoktech XL (the Resurrector at CCV) or a Boge XXL - they will probably give better performance. The other problem with DCTs is that they are slidy (come off of the carto too easy).
There are other very good tanks out there, to name a few: J-tank and it's newer "Fuel tank", the Big Daddy Vapors cartos - Lil
Mamma and Big Daddy, the VPX cartomator, the MAP tanks, the Arry and the Phiniac tanks (expensive, but superb and durable) and many, many more. In general, tanks fitting a regular single coil carto may called "shorty" or "standard", and I for one prefer these. Again, you can use the longer ones, made for DC cartos with single coils. Pyrex and metal tanks are better because they can take any juice and are more durable than the polycarbonate ones which may crack with acidic, cinnamon and other such juices.
To use carto tanks you have to punch or slot the cartomizers so that they can get the juice from the tank.
The other side of the spectrum is represented by the filler-less world: these are cartomizers or tank-size cartomizers that use wicks to draw juice to the coil from an empty, filler-less, container. Look up the "Vision Stardust" cartomizer (aka CE4+) and the Vision Stone tank and the newest kid on the block - "Vivi Nova" (who the hell comes up with names for these?!!). They traditionally are more fiddly than filler carto solutions, may have wicking issues and may leak. However, these newer versions appear to be more reliable and better performing.