Ultimately, taste is a very personal thing. What one person raves about, another will rant about. In addition to the cake, there are a lot of external factors such as the water in your area, brewing method, brewing time, etc.
Instead of my personal favorites, I'd recommend that you buy as many samples as possible from the major sources (Yunnan Sourcing, Jas e Tea, Puerh Shop, Red Dragon Tea, Essence of Tea, etc) and decide for yourself what you like. I would recommend that you try samples from different factories and different regions, as there is considerable variation in processing and leaf flavor profiles. After about eight years of drinking puercha, I've only recently discovered that I'm really drawn to cakes from the Bingdao area. Your learning curve may accelerate considerably from the increased availability of samples. When I began, I blindly bought whole cakes and have a considerable amount of mediocre puerh.
However, if you still really want to leap in and buy cakes, I've recently really enjoyed...
2007 Mengku Wild Arbor King (Jas e tea, Yunnan Sourcing, etc)
2010 Mansai (Essence of Tea)
2010 Yunnan Sourcing Bang Dong Village (Yunnan Sourcing)
2010 Yunnan Sourcing Gua Feng Zhai (Yunnan Sourcing)
(FYI... I tried all of the 2010 Yunnan Sourcing cakes -- except their 'Autumn Harvest' ones-- and the above two were my favorite)
You could also try affordable, tasty basics from
Menghai (7532, 7542) (Available just about everywhere)
Xiaguan (Happy Tuo, Mushroom Tuo) (ditto)
Hope this helps!