Drinks on you?! I need to get in on this discussion...
For me the right decision was high pressure 130s. I can use them with a lower pressure fill and LOVE it when they're full and topped off cold. HP100s are a fantastic tank, though some guys here have them and are making the move to 130s or 119s. If you're a stout lad and can carry a heavier tank around like that, at least check them out before you buy. Let's go diving! I've got, ahem
, one or two 130s around here somewhere.
I also have a couple HP100s too if you'd like to try them. Cost not being an issue, find the right tank by trying them out.
Also, if you can get to one of Grateful Diver's or BDub's gas management seminars before you buy tanks, you'll learn what kind of tank you need for the kind of diving you're doing (or want to do). You will be surprised what you learn... and the math isn't too painful - after all, even dsteding can do it!
Let's go diving!!!
PS: Everyone here is very helpful and is willing to help newer folks get dialed in correctly the first time. Find a great mentor or mentors and learn from them. The board will help with this too. Then, pay it forward. Once you're experienced, help to answer the same questions you asked and take newbs under your wing to show them that there's more to this sport than silt and flailing arms. My OW instructor taught me how not to die diving, my mentors made (and continue to make me) me a good diver.