Uhhggg... who said anything about getting rid of ACID transactions? Seriously, what kind of FUD have you been reading. Transactions have absolutely nothing to do with the format a database uses to store it's data. Most object databases have ACID transactions AND can store your data-structures in their native format.
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.
Gemstone has a free version limited to 4 gig, but few if any object databases are language agnostic, that would defeat the purpose. Object systems are language specific, storing them in their native format is thus generally also language specific.
There's an open source one called Magma in Squeak that's like a Gemstone lite, but I'd take the Gemstone version any day because it'll scale to any level you'll ever need, ever. I'm working on a Gemstone project now, and after having used it, nothing else I've seen comes close to the massive productivity it offers.
By the way, databases shouldn't be language agnostic, this leads to the ever present anti pattern of using the database as an integration point between many programs which turns the database into a giant ball of mud global variable that becomes impossible to change.
Integration databases suck. Application should own their own data and integrate with other application via services. That's how the web became so successful and that's how big ass enterprises should be ran as well, many small apps loosely coupled, not one giant global db where every app is bound to a generic schema that isn't suited for what it actually needs.
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.