Assuming you're talking about AG brewing here I would suggest Summer Lightning, both for it's ease of brewing (few ingredients) and it's lovely, quaffable taste.
For all grain i'd go for something with 100% Pale & one Hop, then when you add different ingredients (e.g. Crystal Malt, Choc Malt) you'll know what they bring to your beer. It's something I wish i'd done when I started.