I do most of my note taking in Field Notes notebooks.
But because these notes tend to get really scribbly and often half-hidden under and between doodles and because I am starting to be really happy about Markdown, I began to use Notational Velocity for those notes I might want to re-read later on. The facts that it easily syncs notes between computers using Dropbox and that it is extremely simple to use work well for me.
To see and edit my notes on the phone, I use Speed Notes which is basically Notational Velocity for the iOS-devices and also syncs through Dropbox.
And as soon as the markdowned note gets to a point where I might want to post it somewhere, I can just throw it into Marked and get a pretty, MultiMarkdown-enabled preview that auto-refreshes every couple of moments.
And once I am in WordPress, I use the Markdown on Save plugin to make sure the blogposts are still usable in case I suddenly decide that Markdown isn’t for me, after all.