If you're using kanger single coils you can't go wrong with a protank-2. Just make sure you get the airflow control base too as they don't come with it standard. That's pretty much as good as it gets with single coils. The regular size protank-2 is 510 and the mini protank 2 (also nice, just holds less juice, more like a glass evod) is eGo.
As far as dual coils go for Kanger, the best place to start is probably the EMOW's. They come in two sizes, the bigger being a 510 connection and holds around 3ml of juice. The regular sized one holds 1.8ml and is eGo threaded. I like these ones the best because they come with an airflow control standard so you don't have to buy an extra part like you do with the protank series.
Myself, I have two regular sized protank 2's, each with an airflow control. A mini protank 2 without the airflow. Two EMOW Mega's and one regular sized EMOW. You'll find some juices taste better depending on which type you're using. For myself, drink flavors like cola or mountain dew and fruit flavours always go in the protanks because the single coil makes a cooler vape. I don't know if you've ever tasted hot cola, but it's sickening. While sweeter flavors go in the EMOW's because they taste better a little warmer. I can only really speak about Kanger's stuff though since Aspire stuff doesn't work for me, but that's for another thread. In regards to what's different between a single and a dual, the temperature change between the two types of Kanger coils isn't actually that much really. You get quite a bit more vapor, but on the downside, duals go through juice faster. Hope this helps!
Here's some links to check out what I talked about.
Single Coil Glass
Kanger Protank 2 Pro Tank Glassomizer
Mini Kanger Protank 2 Mini Pro Tank Glassomizer
Dual Coil Glass
Kanger Protank 3 Pro Tank Glassomizer Dual Coil
Mini Kanger Protank 3 Mini Pro Tank Glassomizer
Kanger Aerotank Mow
Kanger Aerotank Mow Mega - Kanger Clearomizers - Kangertech - Clearomizers Tanks
Evod Mega's as far as I can tell are EMOW's without the airflow control, for cheaper.
Kanger EVOD Mega - Kanger Clearomizers - Kangertech - Clearomizers Tanks
And my first dual coil tank. Evod Glass. Cheap and works.
Kanger EVOD Glass V1 - Kanger Clearomizers - Kangertech - Clearomizers Tanks
Airflow control
Electronic Cigarette | E Cigarette | myvaporstore
There's tons of non Kanger options out there as well. Great thing about vaping is there's pretty much guaranteed to be something out there for everyone. I just use Kangers myself and you said you used their single coils. So I stayed in that family. Good luck!