Email client solutions?

I've been using Mailsmith for years, mostly because it has great email filters. But it's limitations are now working against me, and so I'm looking for another email client. I'm desperately seeking advice about a new Mac email client (or a solution w/ using Mail and plugging) that will do the following:

-Work with my iPhone - in terms of replicating read and replied emails, as well as folders (or mailboxes). It's getting increasingly confusing to work with a division of different message status, and and replies on that appear in Mailsmith but not in Mail on the iPhone.

-Have a flexible system filtering and mailboxes that will enable me to automatically sort message, and will allow for some sort of replication of emails so that I can see the same message in an Inbox as well as in a designated mailbox (if such a feature is possible). It would also be great to have replicant emails existing in two different location, where an email sending can belong to two or more different projects. I would happily consider another suggested system…

-Have variable search options that will enable me to both cast my net wide, and narrow my search with greater specificity.

-Save drafts as one writes emails (to prevent against losing your work during a crash) in the way that the Gmail client functions.

-Set up specific alerts / sounds for individual mailboxes.

-Set up my system so that a specific addresses can routed to particular folders (regardless of whether one sends them to my gmail v. earthlink accounts).

Because I have thousands of emails in my current client, and it will be very tricky to set up a whole new email client (w/ all of the mailbox folders and filters), I want to ensure that I chose the best possible solution. I would event consider using Mac Mail with recommendable plugging that would enable the features that I've listed. What do you guys suggest?

Thanks very much for your help!

Hi. You mention gmail... Is that not an option? It should be able to do all you want.

Re: Gmail, I'm actually in the midst of trying to figure out how to forward my Earthlink POP account to another IMAP account - so that I won't have to worry about space overload (as I do w/ my Earthlink account), and so I can take advantage of IMAP functionality. But...I place a high premium on email security, and have grave concerns about Gmail's data mining. So, I'd love to find a Gmail-like solution, but with the added security protection.

Do you mean privacy, not security? Because gmail is likely to be as secure as any other I reckon, whereas privacy could be an issue due to content scanning, although its only to serve ads, its highly unlikely any human is scanning them or any malicious intent.