If you prefer mouth-to-lung vaping: The Eleaf GS-Tank with their 1.5Ω coils is pretty good. If you prefer direct inhale: I've been pretty pleased with the Tobeco Super Tank Mini I purchased last week. Both of those use (fairly) economical pre-built atomizer heads. If you want to DIY coil and wick: I can conditionally recommend the OBS Crius or perhaps the Billow V2 Nano. (I say "conditional" on the Crius because they've had some issues and I say "perhaps" on the Billow because I haven't tried it, myself, yet.)
ETA: I'm retracting my conditional recommendation of the OBS Crius. It's a neat concept, but poor in design and execution, IMO. Myself and many others have encountered persistent problems with juice leaking from this tank, not, IMO, attributable to wicking or other end-user errors.