I have a laptop with no Windows license (apart from a PC with Windows 7
64 bit and a PC with XP SP3).

Thought I might try Linux. Is Ubuntu the easiest and most stable to
start with?

Any advice on pitfalls etc.

Laptop has a 30 day install of XP on the c drive. Do I use another
partition for the linux software and the third for other files?

TIA for any replies. I have been using MS Windows PCs since 3.1 and
anticipate a steep learning curve.