PHP
In terms of ease, ASP.net and PHP are pretty much on parallels, but once you look outside of that, PHP has the advantage in:
- PHP is open source and free, ASP.net costs $$$
- PHP is almost universally supported, whereas ASP.net hosting is both rare and expensive
- The open source nature of PHP allows lots of new features to be developed rapidly, and thus advances faster than ASP.net
- PHP is arguably more popular than ASP.net, especially in widely-used non-custom solutions
- Much more PHP tutorials than ASP.net tutorials available online
- PHP syntax feels cleaner (that's my opinion though)