I accept what friends say but I just wanna add 2 points:

1. We should not thinks that only Java EE or .NET can build large  scale
solutions. (Can .NET do it?). Lets have some experince and at least try
some relatively less famous solutions such as Ruby, Jini, Zope, CCM etc.

2. I don't think Java is cost/speed optimal for GUI esp. web! If i wanna
chose for web tier, I would like to go for sth. which needs less cosding
such as Velocity(wrapped Java) or ASP(i mean this)