What do you guys think is the easiest skyteam program to earn lounge access?

I think afkl with 30 segments per year

Yup, my thought as well would be FB. It will get you in those lounges with only 30 segments flown per year..

It depends on your travel pattern. If you fly many cheap economy longhauls, Delta might well be better for you. If you fly expensive Business longhauls, AFKL is better again. With many cheap economy shorthauls, it's AFKL, too. As a rule thumb, Aisian carriers tend to have the least generous FFPs.

If you fly often in J, you should consider MilleMiglia, which has a 300% bonus of EQM in J

Is that also the case when flying other Skyteam carriers? And how about flying discounted business?

Except for the Korean carriers in relation to lifetime lounge access. Flying 500,000 in valid fare buckets on either Korean Air or Asiana and their respective partners will get you lifetime STE+ or *G respectively.

If booked as AZ codeshares, yes. Otherwise it ranges between 150 and 200%.

Discounted business is still 300%, Premium Eco is 200%, Full fare eco 150%.

I do not consider this a particularly generous offer. With AFKL you get life-time Platinum status after 10 consecutive years of Platinum status. This means you will need 700,000 miles. For most frequent flyers 700,000 miles with AFKL will be easier to achieve than 500,000 miles with Korean Air or Asiana. Simply because Asian carriers tend to have the least generous FFPs.
(Of course, it's not a bad offer either. If you cannot distribute the 700,000 miles more or less evenly across 10 years time, 500,000 miles life-time might be easier.)

[Remark: I was considering going for Asiana's *A Gold for life as my AFKL Platinum for life is almost reached, but I was put off by the low amount of miles you earn with them. Taking into account the loss of money that this entails, I came to the conclusion that it is cheaper for me to qualify for *A Gold on a regular basis with a FFP that is more generous than to go for the 500,000 Asiana miles.]

Thanks for your help guys

Yup, which is why I said valid fare buckets. *A is my least used alliance so OZ is good to build up miles from the occasional Star flight to slowly get to lifetime, from a redeemable miles perspective the Korean programs aren't that good for earning and burning, especially with the blackout dates they impose.

Pardon my ignorance, but what's FB? I couldn't find it in the Glossary...

Also, is there an Airline code glossary somewhere on Flyertalk?

For finding airline codes, the easiest way is to google them. Type in the code followed by "airline code". In my experience, this is faster than any glossary could be. But you will find a list of aurline codes on wikipedia.

FB is Flying Blue, the Frequent Flyer Program of Air France, KLM and some other airlines.

Delta, if you can get a 25K MQM bonus through an Amex transfer, if they bring that promotion back.

GA's FF program will allow members to reach STE+ after just 30000 tier miles/30 flights or 25000 miles/25 flights after renewal the qualification (but this will be, quite obvious, after GA joins ST)...