Maybe GMail (?).
For one it defaults to SSL and also the ads it runs are from AdWords which is pretty good at limiting hazardous ad content. Google based email.

Not trying to sell you, but that or a MS account (like Outlook or Live) would be more secure. Both of the above are online mail like Yahoo and AOL.

I will say Yahoo's spam filtering blacklist is pretty hard to get off of. Once you get on it, they then check every DNS record, reverse lookup and spf records to be correct before even filtering the content... and THEN (if you've officially asked to be whitelisted) they might let your mail through.
We've had a couple companies come to us for this service; others had failed for months and we succeeded in a week. smile

The power of the DKIM record. smile

I do not work here, but the benefits are still awesome
Make your sound your own!