Having some assistants or even a whole team would be amazing! I'd really love to have some help, not because I dislike working on my comic (far from it, in fact), but because I'm always afraid I won't be able to finish it if I work on it all alone. The stages I enjoy the most are sketching, toning and lettering. That said, I think I'd leave inking to some of my assistants. I wouldn't leave it entirely to them, but rather split the pages. Each of us would have an amount of pages per chapter to ink, in order to conclude the work faster.
Also, I think I would leave backgrounds (especially the inking phase) to someone with more experience than me, who can produce good and consistent backgrounds. I'm slowly getting better, but I'm still weak on the lineart and I have a lot to learn!
Last, but not least, I'd hire a colorist to produce a colored version of the series. I'd probably publish the colored version on internet and print the b&w one, although I'd also love a printed colored version. Anyway, this is still a dream of mine and I hope I'll be able to make it come true, even though I don't have my hopes up 
Edit: It just came to my mind right now, but I believe I'd also hire someone with experience in marketing in order to promote my comic. I'd leave the task up to them, since I'm not very good at it.