Some questions before buying MacBook Pro

1. Most of them yes, however there are some things to be careful about.
   1. The new Mac OsX (Mountain Lion) limits any USB device (other than apple devices) to get more than 5 Watt power from Mac USB ports. This might create some inconvinience. For example, I had a USB 3.0 Hard drive (Toshiba), which according to other people and Toshiba, tries to take a little more than 5 Watt energy. On Montain Lion, I cannot even mount it as OS automatically shuts down its power request.
   2. It depends on wthe kind of USB devices you mention. Almost all USB devices need a device driver to run on any OS. Most of the standard ones (such as external hard drives or mouses) have universal drives that are either included in any OS now or in themselves so they don't create a problem. However, if you have a non-common USB device (such as a USB controller for a racing game as a stirring wheel), then it might only have drivers ready for Windows and thus not work at Mac.
2. Both (via Wireless and through USB) should be possible. If you still have the box of the drive or know the model, I would suggest you to search it in the Internet and look for the specifications (I am sure that it would list the compatible OSs).
3. You cannot run Windows Office apps on mac directly. You can either buy their Mac equilavent (also developed by Microsoft with the same name) or you can install Windows on your Mac (either dual boot with boot camp or through a virtual machine) and then run your Windows versions inside Windows. In any case, both applications (either Mac equalivant or through Windows) will open your existing files. However, note that not all Office applications are available for Mac (e.g., there is no OneNote and hence you cannot open your OneNote files on a Mac).
4. None of the Windows software (especially if they are installed through an .exe file) can be used on Mac directly. To use them, you can:
   1. Look and see if they have Mac version. Most of the software has both versions nowadays. If this is the case, just download and install the Mac version.
   2. Look for a Mac software that does the similar things. Ask to forums & make a google search, you can almost always find this if your software is not extremely domain specific.
   3. Install windows on your mac (either through boot camp as dual boot or through a virtual machine such as parallels or VMWare) and run the software on windows.
   4. There are some emulators such as WinOnX, however I would not really suggest using them to emulate your software. They are quite hard to setup and they are ugly hacks over Wine (a project that tries to port windows to linux) and they are guaranteed to make you cry at least for some of your applications.
5. If you are happy with read only option, no. Mac Os X can read any Windows formatted hard drive (NTFS). For write options, you have to reformat them into either HFS+ (Mac format), exFat (compatible format Mac & Windows) or Fat32 (more compatible than exFat, however cannot have a file more than 4 GB). I would suggest exFat if you are looking for compatilbility. However, if your external hard-drives are already Fat32 or exFat formatted, then you don't need to do anything, they will work immediately on your Mac.

Hope this helps.

1. It will take any usb device - like the ones connected to your pc as long as it's MAC/PC compatible device.

2. It can be used in the network device - but might have issues if formatted to NTFS. Your Macbook can read it but can not write to it.

3. You have to purchase Office for MAC. You can open a word or an excel file saved in a PC with your Office MAC. If you don't want to buy Office for MAC, you can download LibreOffice or OpenOffice - Free.

4. You can install Windows via Bootcamp and run your Windows Apps from there.

5. Yes, if you want to use it with both Mac and Windows, you have to format it to extFAT.

I might be wrong with number 2. But I'm sure someone will jump in with their suggestions.