oh cool, I just found out about this thread, its so hard to start, i love tea and used to teach people about tea when I was living in Germany.
So my favourite has to be in the oolong family, especially Taiwanese high land (gao shan) (1200+ meter above sea level, harvested in Spring, about 15-20% fermented, 2nd-4th tips (grand cry in wine term) the 3rd-4th water would be optimum for me, and infused in my trusty Yixing clay pot.
another spring oolong tea would be Fujian Ti Guan Yin (800+ meters above sea level), 55-65% fermentation, big leaves (3rd - 6th tips), 2nd - 4th water and infuse in the same Yixing clay pot.
Green tea... my mom knows more about green tea than me, but since I used to lived in hangzhou (the place of the best green tea, Longjing) I had my fair share of green tea to drink, but my favourite would be summer harvest of Korean Je-ju island green tea, I dont recall the name, but i get it from this place all the time and they know what I buy, its not like normal green tea because in Jeju Island it gets more sun, so it has full-flavour, can even called "creamy". Infused at no more than 80 degree celcius water, otherwise the tannin would come out and taste bitter.
other notables that i drink on a regular basis... Huangshan mao feng, big leaf (minimum 30cm in diameter) Pu-er, lose or pressed doesnt matter, 8 years old minimum of post-fermentation. but puer is a totally different art of tea which again im not an expert on, but it's good after meal helps dissolves fat, thats why its the main ingredient on diet tea.
Oh I should stop now, can talk about tea all day and all night!