I am buying a Macbook Pro today because it is a Mac, but I do need to be able to use some of my business Windows stuff - like MS Access which has my customer data base. I have more that 12 years of business stuff in Windows.
I would be really happy if I could convert Windows file to Mac.
Hank
The files wouldn't need any conversion to be able to run on a Mac vs. a Windows PC, you'll just need to make sure you have a program to read them.
You'll have a few options to continue using your MS Access files. The first would be to obtain MS Office 2004 for Mac, which runs in OS X and reads the same files types the Windows version does. (It's not Universal Binary as of yet, but it still runs quite well, I use it frequently).
The second option would be to install Apple's Boot Camp software, and have the option of booting into Windows when you need to, to use any of the old programs you'r familiar with. (Keep in mind, there are some requirement to be able to do this, like having a full copy of XP with SP2, more info is on Apple's site).
The third, which sometimes might be easier because you wouldn't have to reboot into another OS, would be to use a program like Parallels Desktop, which allows you to run Windows (or Linux) inside Mac OS X. It doesn't support 3D video, however it runs quite smoothly doing most tasks. Just don't expect to play games in it!
I have all 3 on my Macbook Pro, and they all have their uses, so I can't really say which is the best option. You may not care about 3D gaming though, in which case Boot Camp might have less of an appeal...