Email clients needs to evolved, what do you think?

Hi, I'm a freelance developer and I have a few clients who email me sometimes dozens of times a day. So each day I wake up and have to parse through my emails to find which are the most importants, which contains PSDs files or mockups that I'll need to check and send feedback, etc.

All of this is very frustrating with only a little panel to see my email list. This whole "view" is flawed IMO.

I believe email clients should have something more of a "file browser" view with medium/large icons (enough to content from/title/date/etc) and easy way to put emails to different folders. So you can have a peek at the whole inbox at once and quickly eliminate non important emails.

Also I think email clients are in great need of a very good filter system with easy access. Gmail filters are amazing but I'm having a lot of trouble using Gmail on a daily basis I just don't know why. I think filters should be more easily reachable. So I'd make a "Contains pictures" filter, a "Contains text document" filter and a "VIP" filter for very specific person that I know sends me email only on a very important basis.

All in all, I don't have a clue about how it should look. Every last attempts at email clients I saw were in my opinion disastrous. There's still a few projects ongoing but I still doubt any of these will change this fundamental problem.

It's not about the protocol, emails are fine I don't want another Google Wave I just need a better way to manage these messages. Sparrow is nice, I use it daily even if it's not in development anymore but it's not enough powerful, it has a lot of wasted potential (since development stopped).

One last thing: I tried several other email clients with power features but all of them have crippled UIs and almost no development updates anymore.

So let's discuss, what do you think? How do you manage these tons of emails? What do you use? Any suggestion for me about how I handle them and what I should use?

Thanks and have a nice day!