This has been a long-running (standing/sitting in a box?) project, I got some nixie tubes, in ooh, it must have been 2002 but have never had the guts to make a high-voltage (albeit very low current) controller board from scratch. Fortunately the nice people at Arduinix.com have come up with a simple board which uses cheap Russian BCD demultiplexers for not too much money.
So far I’ve built the board and tested it with a single tube (at 170V) which works fine:
Anyway the build page is here: http://www.zoot.org.uk/wiki/index.php?n=Projects.NixieClock