For Applications which is favorable - Microsoft software/OS or Sun/UNix/Linux

[SS]

hello ppl,

recently Microsoft came up with new VS2005 and also
their servers(exchange, SQL Server) became more robust
and powerful

but it seams to be that they are trying to take the same
steps like Sun or Unix/Linux free software foundation's
approach of attracting lobbyist and professional.

How you rate it? Which software is still reliable for
corporate develeopment? I know security wise Linux/unix
is unparallel but what's the hype about new
.NET arrival?

Your thoughtful advice on the following really appreciated it would be great if the advice considers the high effectiveness
of the system and low cost to build and maintain it. thanks

Application development platform - ?
(small business in future it might be robust and also compatable to different applications)

Servers-?
web and office development software-?

is there anything else that i should consider??