It is interesting to note that the only "mainstream" way to view SVG is through the Adobe SVG Plugin. There are many other viewers (the most well known being the Apache project's Batik Java viewer - although that doesn't have dynamic scripting functionality yet).
However, it is difficult to see when there is going to be fully standard SVG capability deployed in the majority of browsers (not necessarily fully compliant - just something that you know works the same everywhere).|
I don't know who I'd choose as the lesser of the two evils between Macromedia and Adobe - but the Flash vs. SVG battle really boils down to the rivalry between these two.
I admit I drink from the Flash cool-aid but there are still some things worth noting:
Flash MX player - 380 K
Adobe SVG viewer - 2.24 M
SWF, the Flash file format, is open (even Macromedia has described it as such) and there are several open source libraries for producing it in C++, Perl, PHP, Python and Java (plug).