I have never used the stock email program, but I have a fair amount of experience with K9 now.
K9 gives you the option (at the account level) as to whether or not to bcc yourself.
K9 does give an "audio notification" for all messages, but one of the default options for the sound is "silent". I use this, as I also get a lot of mail and would go nuts if my phone beeped every time something new came in. It also allows you to select whether or not to vibrate on new mail, whether or not to send a notification to the status bar, whether or not to have an LED notification, and if so, choose the color of the notification. None of these choices will affect your text message notifications in any way.
All these K9 settings exist at the account level (not the global level) and it can be a little hard to get into the account-level options if you don't know where to look for them. You have to be in the account (not the combined inbox) then select "menu", then "more", then "settings", and then "account settings". If you want all your accounts to behave the same, it's a little bit of a nuisance that you have to set everything for each one separately. On the other hand, you only have to do it once, and it does give you fine control over the notifications you get.
I've been pretty satisfied with K9. And it's free. As in, really free. It doesn't even serve you ads or stuff.
Puzzlegal, I really want to use K9 or Kaiten for all of the reasons you've listed above. However, here are my challenges with both programs and maybe you can help me.
1. If I scroll down to the middle of my inbox to read a few messages
then switch to a different app; when I switch back to K9/Kaiten, the inbox automatically scrolls back to the top. Therefore, I lose my place EVERY TIME and have to remember how far down I was in the inbox. Any fix for this?
2. When reading an email in Kaiten, is it possible to make the LEFT navigational arrow bring up the next NEWEST email (going UP in the inbox) instead of the next oldest (down) email? (This works perfectly in K9)
3. When reading an email, if I switch to another app then return to the email, none of the navigational buttons work (ie. the arrows or volume buttons) to allow me to move on to another email. I must hit the back arrow to get to the email list which of course automatically scrolls all the way back to the top of my inbox and loses my place. ARGH!!!! (see #1)
4. Is it possible to change the font color in the signature and when
composing new emails?
5. Is it possible to change the font type (ie. Times New Roman,
Courier, etc.) in the signature and when composing new emails?
Is there another IMAP client out there that does NOT have these issues? In addition to K9 and Kaiten, I've tried Enhanced Mail, Touchdown, MailDroid, Moxier Mail, and the stock app of course. They all seem to have various issues. Maybe I'm expecting too much out of an app. The stock email app on my Palm Pre worked well for me!