Instead I think the question should be, "Whether Smalltalk?" And the answer could very well be yes.
VisualWorks 7 is loaded with Internet capabilities: servlets, server pages, SOAP (Open talk). The VM is so much more mature than the CLR and JVM implementations.
The company appears to be solid, and has backed VisualWorks longer than anyone gave them credit for. Cincom rescued Smalltalk from history, after ParcPlace nearly bungled one of the truly great software systems of all time.
S# appears to be close to release for dotNET. Not only could this put some spark back into Smalltalk, but it could pave the way for widespread success of dynamic languages in general on the CLR, through the collaborration with Microsoft and the specific implementation techniques.
Not to mention that Dolphin and MT are still solid Smalltalk implementations for Win32 and on multiple platforms Squeak and GNU Smalltalk are too. The combination of VisualWorks and S# and these others make a cross-platform opportunity for Smalltalk. Systems built for S# or VW to a large degree should run on the other.
VW 7.1 is supposed to provide a more solid (non-beta) native Mac OS X implementation and VW is already solid on Linux and other Unix systems.
Smalltalk is a simple, classic notation for expressing computation. Code written 20 years ago still runs on modern implementations.
Why build important computational assets in notations that are overly complex (i.e. they make you say more than necessary) and are tied to implementation decisions that will soon be outdated (i.e. the "standard" notations are regularly updated with new features that compell adoption by marketing lust and lead to a chronological stratification similar to carbon dating)?
Java and C# books become outdated in a year. They no longer teach the notations the way developers want to use them. On the other hand, a developer can learn 90 percent of Smalltalk by picking up 1983's Smalltalk-80: The Language and Its Implementation!
Far better to build your important computational assets in a notation that is already long-lived, simple, flexible, and efficient, not to mention mostly unchanged for 20-30 years or more. There are a two of these notations that make sense to me: Lisp and Smalltalk.
I could go with either. Smalltalk is easier to explain to developers using other object-oriented languages.