Spen 77
Raidlight olmo . Two bottles riding high up on the shoulder straps. You can drink using the straw system without taking out the bottles. Well balanced . The 20 l version is big enough for 99% of ultras and they weigh so little that you only need buy the one pack. If you stiffen the half empty pack with bubble wrap its fine for short ultras. I can cram all my gear for a 2 day Mountain marathon in mine (just!)
The only down side is that they are built so light that they eventually come apart. Having said that I have done UTMB L100 and about 8 mountain marathons with mine / + loads of training runs and shorter ultras . After 4 years of serious abuse it has finally had it and I am now stitching the bottle holders onto my other Raidlight pack ,shoulder straps as the system works so well.
Edited: 05/01/2013 at 19:19