Where are you going to dive? Places like Curacao you'll never be asked for AOW cert and you won't benefit from Deep unless you're so prone to narcosis you're getting narc'ed in a swimming pool.
sorry but i am not sure i would agree with this post.
i would agree that getting padi advanced is pretty much a waste of time unless you are required to have it to move up the padi training ladder. i actually took a padi adv course years ago but the cost between paying for 5 dives and taking the course was only about $50. so for me at the time it was well worth it.
an ssi adv cert however (just for example) is a different story. you need to complete four full specialty courses in order to be awarded the adv open water diver cert. (you need to also have at least 24 logged dives). so there is a significant different between the padi adv and the ssi adv cert.
as far as a deep specialty being of no benefit.....i think i would also take exception to that comment.
for many divers, going beyond the depths they trained in is a very nerve racking idea. some feel much more comfortable easing their way down when they are along side a trusted instructor. there is also more theory and dive/gas planning that can be learned from the course that many divers have never been exposed to.
it may not be a nesessary course for all divers as some are lucky enough to be able to dive with others more seasoned than themselves and they can learn many of these skills just by being in that group. but everyone is so lucky.
after open water i like to tell my students to consider what they eventually want to achieve, and then try to choose training that will get them there.
nitrox is usually a good one to have. it is def necessary if you plan on ever doing any "technical" dives. navigation is a very necessary course especially for those that have never even looked at a compass. i think deep can be a great course with the right instructor. etc etc