Classical Rider Waite Smith. Or Radiant RWS if you prefer brighter colours. Or Robin Wood, it is very similar to RWS, but if you dig the pagan/celtic iconography can work better. Basically Rider is the best one to start learning, when you're done memorising all the layers of meaning encoded in every card you could perhaps move on to a less traditional deck, but most of them are still Rider-based to a greater or lesser extent, even the less conservative ones (like Joie de Vivre, Steampunk or Arthurian Legend for example)
Aside from this tradition, there is Marseille / Visconti, which are basically derivatives of medieval/renaissance playing cards, whilst the majors and court cards look interesting, the pip cards don't really have any imagery, so might be a challenge reading them (I don't own any of these decks)
The third tradition is known as Thoth (Crowley-Harris), the symbolism is a bit more complex and requires more studying. There aren't that many decks that could be labelled as Thoth-based.
So I'd say just start with RWS or one of its more conservative variants and download Arthur Edward Waite's "pictorial key to tarot", this should get you going