The first strain I ever ran, about 4 years ago, was Pure Power Plant by Nirvana. Awsome yeilds, easy to grow as it was very forgiving to a new growers mistakes, and a surprisingly good smoke. I grew this strain for 3 years and wish I had not stopped. Indoors as well as outdoors it is a fine producer.
I'm currently running a strain by Royal Queen, Critical, that looks to be very promissing. I cant verify the potency yet as its about a week from finishing. Its a very fast finishing indica dominant strain that shows to be a top producer. Another easy strain that should be good for beginers as well as advanced growers. I'll be growing this one outdoors as well.
Afghan Kush by White Label seeds is another that is a very fine producer, 51 day flower time, Indica Dominant. I'm growing this at the moment as well and am very impressed by its yeilds.
So many strains.... So little time