You really need more requirements than that. Most of those are more of the subjective features that anyone can "claim" to be. As for my personal opinion, I've used Hostgator (dedicated server tho) and they are awesome, as to be expected. They have three ecommerce softwares they provide also (ZenCart, CubeCart, osCommerce).
Customer support with a real phone number is very important. When you have an issue, time is money in e-commerce, your sale just went to your competition if your site craps. It is imperative that you can call and talk to someone to get the problem solved as quickly as possible.
Right... tech support ( Free tech support ) who are available 24x7 via different communication medium like Live chats, emails/tickets or through Phone support is a must, also we should check if offered hosting plans are managed hosting packages !!!
None... and almost all at the same time. I don't want to sound rude, but do you really understand the point of this question? It's the same like asking "what engine is best for XXX oil?" - it simply does not make any sense. I believe you will be using one of standard e-commerce systems and most hosting providers will handle it without any problems.
Liquidweb is my favorite. I'm with them for a while now. First on VPS and now on a Dedicated. You can't beat the support. You get a real person on the phone if you have a problem and they fix it in no time.
On the point of running a ecommerce site via shared hosting - I read (but have read wrong) that you can only have 1 ssl cert per shared host. i.e. reseller hosting Is this correct?
No doubt go with HostGator, Recently I changed my old hosting webhostingpad and Moved to HostGator then looks pretty good from other hosting out there
Not really. It depends on your hosting providers. Most of hosting companies allow only one SSL to be installed on hosting account, while some others allow having dedicated IPs even for reseller sub-accounts (for extra fee)
If you have chosen e-commerce solution already, then you need to choose a hosting company depending on system requirements for the software. Otherwise asking for advice of ANY hosting company is just a waste of time.
I agree, Hostgator is good hosting, especially for beginners, or for people that use light web applications. Their on-line support is absolutely fantastic.