I'm thinking 200k nodes and 2 million edges? Graphviz segfaults graphs a fraction of the size and even at that scale a node by node representation isn't super helpful without being able to zoom out and look for patterns.
Gephi and Cytoscape are the main free graphical applications for analyzing networks; they might work for you. Tulip [2] might also be worth a try.
[1]: https://web.archive.org/web/20111102185002/http://www2.resea...
The idea is by connecting GPUs in your browser to GPUs in the cloud, we can do bigger and bigger datasets over time. We're currently 1M nodes & edges in interactive-time (so no leaving your computer for 1hr+ or crashing), and actively working on the V2 engine to get us to 100X more. And yep, generally we don't want to stay long in large views, so we see it more about being scalable / smart / usable enough to let you go in-and-out.
There are some tools in R and python that seem to turn up. I'm sorry I don't have anything more specific than that to suggest, though it might be a fruitful direction.