Well, it's about time for me to transfer hosts. I'm beginning to get fed up with my current host's tech support and forums, plus it's getting more expensive, but this is besides the point. I have 2 main concerns when I perform the move:

1. Information Transfer
I currently have two sites hosted with them, they're using cpanel (My future host will too, I'll make sure of that.). Does a full backup through cpanel cover absolutely everything, including all email data, mysql databases, all my files on the public_html directory, etc.? (just want to make sure I don't lose anything during the move).

Also, when I generate the full backup via remote ftp through cpanel, does it basically "duplicate" everything to the other host? If so, then what happens to all the data on the old host?

2. Specific Requirements
Like I said in point one, I currently have two sites hosted with them, and I'm thinking about starting another website, along with possibly selling my current blog (see this thread for details, so I'll have either two or three sites total). Right now I'm assuming the best package generally to go with would be a cheap reseller account, but I'm not 100% sure on it (With two blog sites, and one forum site.).

Well I recommend you go with a reseller account. Also get your own private label nameservers for your reseller account. This will help you in future, when upgrading to a dedicated server or switching hosts and you have to change the nameservers of each domain.

I recommend Hostgator to you. They will transfer your both the domains to your new account without any hassles.

Also, when I generate the full backup via remote ftp through cpanel, does it basically "duplicate" everything to the other host? If so, then what happens to all the data on the old host?

Data on old server remains as it is. You will need to manually delete the data, once the new setup is completed. Since it will take a couple of days for the domain to resolve, you can do a 301 .htaccess redirect to the new server IP. And it will be safe to delete the old server data after a week of completeing the transfer.

Actually wouldn't shared hosting be better for me? It's a heck of a lot cheaper, plus with your hostgator mention, their "baby" plan allows unlimited domains. Shouldn't that be the type of plan to look at right now, also since my traffic numbers aren't that high (maybe about 100 hits a day or so)?

maybe about 100 hits a day or so

Pretty much any host that can keep its server online and has good support would work then.

Actually wouldn't shared hosting be better for me?

It should work just fine. "Better" is much a matter of preference. john551 actually listed the reasons why a reseller account would be better for him.

A person may think that a sports car is the way to go, another that the SUV is the best thing since sliced bread.

Doing a full backup in cPanel should be enough. If you were changing the domain of the site, then that would be problematic, but you're not so it should be fine.

Shared hosting seems to be the best option for you - a reseller account is overkill to be honest if you only want 3 or 4 web sites. Instead, make sure you have the ability to add additional web sites (i.e. with addon domains).

100 hits a day is a fairly small number and I would expect all hosts would be able to accommodate for this.

Good luck with it