I have discussed this elsewhere - however - I could not pass on sharing this here as, like myself, the number of Mac users in financial services continue to creep upward. Some industry estimates have it at 3%, which although a small share, adds up to a tidy number of users. Additionally, I have had a number of conversations both at conferences and in email threads with folks who have switched or are assessing a conversion.
One of the biggest obstacles if often Outlook. Not necessarily the email client itself - but the massive email archives contained in what Microsoft dubs the PST file on Windows. The methods for migrating this information over to Mac - even on Microsoft Office for Mac are generally speaking fearsome sets of instructions that scare off most folks.
That has now changed with a friendly utility called Emailchemy. These folks have developed a solution that actually can convert a large number of email types - most importantly Microsoft Outlook for Windows to a number of email clients on the Mac platform. I recently used it to convert over 5,000 messages and attachments over to Mail.app on a Mac running Snow Leopard OS X. This exercise took 15 minutes - including getting the email database off of a Windows computer, copying to a USB thumb drive and then converting onto the Mac.
The software can be used by an individual, a "household" and even for larger migrations. The entry price is $29.50 for a single user to convert as many PST files as needed. I would recommend a look at this software if it is a task you need to accomplish.