* My first consideration would be... how confident are you in playing around with your partitions... Data loss is always a possibility and we'd like if that wasn't associated with installing Mint
* What kind of hard disks do you have? There are some extra considerations to make with a combination of drives... i.e. SATA, PATA, IDE... If they are all IDE, my experience has been very good. However, if you have the other 2 types, I strongly recommend you read this first: http://www.linuxmint.com/wiki/index.php ... annot_boot
* Is this your first Linux install? If it is, I would suggest you keep it as simple as possible... to avoid possible sources of problems. You can always spice it up later... in a future installation or without reinstalling if you know how. If you have the different drive types as mentioned above, I would suggest installing using mint4win... at least until you are comfortable enough with Linux to step up the game and handle possible problems with the different drive types.
Now, your questions...
1) as Fred said... not more than 2x your RAM and the total should not me more than 4GB... So in this case, your Swap should not exceed 2.5GB. 1.5GB is already sufficient for most tasks... but if you are going to be running memory intensive apps like image or video editing, then go closer to 2.5GB... otherwise, anything above 512MB should be enough.
2) All you have to do is create swap partitions on all your drives... then add a few lines to /etc/fstab.
3) the size of /home really depends on how much you want to put in it... You should have at least a few GBs to have space for user settings n stuff. For /, 10GB should be enough even with all kinds of junk installed. As for data partitions, use the partitions you use for Vista... that way you can access them from Vista as well.
4) I would suggest not creating separate partitions for /boot, etc right now... if this is your first install... keep it simple for now.
5) If you run Windows programs in Linux, you will be using Wine... which will create it's own 'C drive' (which is just a folder) in your home folder. Try finding alternative Linux apps instead... they will run much better.
6) Only one OS will be used at a time... so I don't see any difference in performance between the two set ups.
Again... if this is your first installation, try out mint4win. You can allocate as much space as you want to Mint... At least until you are comfortable enough with Linux to take it further... and be able to fix a failure to boot scenario if it happens... since you will have to fix it in Linux.