its tricky because windows doesn't really like non-microsoft bootloaders. LILO can work but may cause problems with windows. GRUB is decent. Someone I know uses XOSL which works quite fine (so far...).
I have been using BootItNG and it is a fantastic boot manager with some other neat utillities to go with it. I haven't much experience with linux so I don't know what compatabilities/conflicts it has. But with the free trial period it might be worth a look at as it allows you to put hundreds of OS in as many partitions as you want. I run 5 different windows OS and each one is tagged for what it was set up for with no conflicts for over 2 years.
GRUB definitely. In anycase, you shouldn't worry bout the bootloader. All GNU/Linux distributions come with GRUB. I believe LILO is out of commision these days. The worst bootloader would be the Windows one.