No regrets, even though I had the USB connector agony and I've been without the N900 for nearly 3 weeks while I persuade Nokia to do the right thing! The N900 is the ultimate Swiss army knife of mobile devices: it does pretty much everything, and if it doesn't then finding solutions is rarely far away.
Could it be better? Sure - longer battery life, better bluetooth, maybe... However, compared to other devices it wins on all-round capability, IMO.