If you're concerned about one distro's settings altering another's, you can still use a common /home partition - just don't use a common username also. username1 username2, or perhaps more logically username.distro1 username.distro2 etc. Just my 2 cents.

You have to check with the distros you are interested in. All the big ones do.

Edit /etc/fstab accordingly. That's all.

But, unless it changed recently, Qemu is different... For performance, you may prefer virtualbox or vmware, if you want to emulate an exotic CPU, go Qemu.

Wine

The "64" in "Athlon64" most likely stands for 64 bits.

On programming, J is my programming language of choice. (Go to jsoftware.com). It is mathematically oriented but can do anything else. Ken Iverson created J as a version of APL which uses ASCII characters. It is the most logical language. It deals automatically with vectors and arrays so there is no need to to define things. The help to get you started is extensive.

I'd recommend keeping separate /home directories per distro for reasons already mentioned. You can keep them fairly small and 'clean' by moving personal data (documents, mp3s, etc.) to a data-partition which can be shared by all distros. Perhaps you considered that: "56GB FAT32 Logical (File Storage)" but I'm not a big fan of FAT32 for data, I'd rather use Ext3 (and an additional FAT partition if you really need one).
For convenience you can add a symlink to that data-partition to any /home you're regularly using; the partition then functions like a directory in /home.

Do you expect to be using many memory-hungry applications at the same time? If not, maybe you can slim the swap partition.