Some of these new fangled distributed databases forgo transactions because transactions and distribution don't really go well together, they are opposing forces. Don't confuse issues that have nothing to do with each other, and don't assume that only relational databases support ACID compliant transactions.
Look at a real object database like Gemstone that is directly comparable to your big iron Sql database. These new distributed key/value pair database are little more than distributed persistent hash tables, they're different beasts entirely and aren't directly comparable in features because they're meant to solve different problems.