Looking for an email client that can...

[Automaton]

Hopefully this isn't a repost...

I have the Sprint Mogul/6800. I set up the messaging software it came with to access a mail account using POP3. It downloaded all the headers, then I tried to access a message. I couldn't immediately view the message. Instead, it wanted me to save the message to my device the next time it did a sync, and then let me view it. This isn't what I was expecting, and kinda sucks.

Is there a mail client that will let me download all the headers, then allow me to view and reply to messages on the fly without saving them to my device? Or is there a way to configure this kind of thing on the Mogul's messaging software? I realize the messages wouldn't be available offline, which I don't mind. Basically I want it to behave as if I was logging into a web-based mail client.