And you'd be right... to a point ;-p
The C# 3 changes are largely (on the surface) some minor compiler
conveniences - but good conveniences. Extension methods, for instance,
I've already used in a number of scenarios completely unrelated to
LINQ. Many of the features tie tightly to eachother - for instance,
anonymous types demand the "var" type inference. Lambdas (as
delegated) feel cleaner than the older syntax, but yes: *by itself* it
isn't a killer feature (although the facility to compiler to an
Expression rather than a delegate is /extremely/ powerful - but
obviously demands .NET 3.5 [which C# 3 itself doesn't]).
However, the features really come into their own when considered with
their relationship with LINQ (.NET 3.5). Almost everything in C# 3
relates to LINQ in some way, so it is hard to evaluate their use
without some mention of LINQ. I started typing an "in particular", but
to be honest so much of the changes tie to LINQ that it became
unnecessary. Maybe auto-properties don't tie to LINQ... but that's
about it...
Regardless of your thoughts of LINQ-to-SQL etc, LINQ surely represents
an extremely powerful and expressive step forward, which hopefully
will make it easier for code to indicate what it is trying to achieve,
rather than masses of step-by-step how to do it.
This again important if you want to use things like PFX (or Parallel
Extensions, whatever they are calling it now), which is important
given the migration towards multi-core computing - the compiler can't
do anything with overly-specific code, but if you express your intent
and let the framework worry about implementation (rather than having
to continually write lots of parallel plumbing, and making lots of
mistakes in the bargain) you are onto a winner.
If you are interested in more information about the C# 3 particulars
and their advantages [or just more info], rather than focusing on
the .NET 3.5 details [which are of course mentioned, but only to
explain the "what?" and "why?"], then I can recommend Jon Skeet's
forthcoming book - it is /heavily/ geared toward the language rather
than the framework.
http://www.manning.com/skeet/
Marc