Riverstar, you're incorrect. With the exception of specific Bard songs (Battlecry/Warsong of the Vah Shir, Rizlona's Call of Flame, etc), Bard haste songs *do not stack* with spell haste. As I explained below, while the Bard song will still take effect on someone with a haste spell, only the highest haste effect will count towards the actual haste number. So, if you have enchanter haste of 60%, and a bard song giving you 30% haste as well as other effects (str, dex, whatever), the 30% bard haste component will be ignored. For a great explanation of this, check out this post on The Concert Hall. It's the most clear, concise and accurate description of haste stacking that I've seen so far.
Azrielgavan, yes, war song will stack with other haste songs. All of the stackable-haste Bard songs will stack with the non-stackable haste songs. Two stackable-haste songs, however, will not work together (they are the same line, so the weaker spell will be overwritten).