Oh! My Goddess (or Ah! My Goddess in the native Japan) has been around for a long time, but here's where it all started - the manga where a luckless young Keichi Morisato dials for a pizza and ends up with a Goddess for a girlfriend. The subsequent trials and tribulations involving his new girl Belldandy's sisters, Urd and Skuld, as well as several demons, spirits and household vermin all start right here. And while the manga really does look its age now (especially compared to the current, streamlined characters in the 2 TV series) it's still as fun as it ever was.
Of course, much of this first volume simply sets the groundwork, and despite a few teething troubles, it really is (comparatively) smooth sailing at this stage.
If you're looking for a magical girl series to get your teeth into, this is one of the modern day classics. Every chapter is a standalone tale, and each oozes an innocent charm. While those of us who are a little more mature might balk at Keichi's naivety and Belldandy's sugary sweet good nature, it's not long before the real heroes of the book turn up. Urd is a modern day hero, and her sexy exploits and constant match-making are always a joy to behold. Truth be told, many of us would give the young lovers a similar shove in the right direction were we in her situation. Of course brat extroadanoire Skuld is soon on hand to provide the Ying to Urd's Yang, and the results are generally explosive at best.
The cast of characters soon becomes extensive, and we're left with a huge group of selfish ne'er do wells, dopey (and insane) friends, love rivals, relatives and demons messing things up left right and centre. It may all seem a touch cliche now, but it was still pretty fresh at the time.
OMG is worth fishing out if you've exhausted all the modern equivilants, (hell, even Tenchi is modern by comparison!) but to a younger audience this may all seem a bit sedate and frilly.