Make your Apple Mail look right in Outlook
One of the many problems with Apple Mail is the way that it handles typography in rich text messages. You are able to set ‘Message Font’ under ‘Fonts & Colors’ in Preferences, but this is a little misleading. What you are actually setting is how you would like to view your own emails, not how others will view them.
Whichever font you choose in Preferences, your messages will most likely be shown in Times New Roman in Outlook. This font is not the first choice for most graphic designers, and I find it strange that Apple has built the application like this – especially knowing how much Steve Jobs himself cares about typography.
Sometimes the solution is almost too simple, and for now I have found that the solution is to make a signature for each account. The signatures will always be displayed using the correct formatting. If you add a few empty lines with the format of your choice before the actual signature, and make sure you always start typing after the second or third line of the new message, your emails should end up looking the way you intended.

August 12th, 2007 at 1:55 pm
Thanks for the tip. I’m having the same problem using Mail at work. When I view messages I’ve sent from Mail in Outlook the fonts are either (1) in Times New Roman, (2) completely messed up (wrong font, wrong font size), or (3) a combination of 1 and 2.
Note to Apple–there’s a small e-mail client out there you may have heard of called “Microsoft Outlook” which can’t read Mail’s fonts properly. You might want to look into it. Or not.
September 10th, 2007 at 7:25 am
Guess what…Mail 3.0 for Leopard hasn’t fixed this, not in build 9A527 at least! Can you believe that!?
September 11th, 2007 at 10:08 am
mountainbiker801: I have seen this problem discussed many other places while I searched for a solution, and it is very much unlike Apple to not address this. Let’s at least hope there is a more elegant workaround available.
November 28th, 2007 at 2:24 am
I’ve been struggling with the same issue. It doesn’t look good when I claim to be using a superior system but cannot make my emails display using the corporate standard. It just isn’t right!
December 5th, 2007 at 9:10 pm
Thanks a million for this workaround - as a new Mac user I was dumbfounded and very disappointed by Apple’s stupidity on this. At least there is a way round it. However, Apple really need to sort this out urgently, it’s completely unacceptable.
November 27th, 2008 at 8:04 pm
Wonderful tip!!!! I’ve been trying to find a solution for a long time. This Mail “feature” drives insane anyone dealing with Outlook users.
Thanks very much!