Forget the semi-retired thing and just retire.
I retired at 55, I was also in IT, an Oracle DBA, and I know it's a cliche but since doing it I've never stopped enjoying myself. I thought I'd miss the job but I didn't, what did come as a massive surprise was to find out that I wasn't meant to work. I was definitely meant to play all day.
Oh and you'll need the bike for the aforementioned playing, one bike just isn't enough.
As an aside my on-line name is work related Mr Toad - Tool for Oracle Application Development.