For mega important stuff I will use only 1 company, but do NOT expect them to be cheap or even offer you a per domain price.
http://comlaude.com/
Nick Wood is the guy to speak to there.
For the equivalent if you're US based I would guess that MarkMonitor is the most obvious choice - but both are pretty much priced at the large corporate client level.
Monte leaving Moniker will inevitably have an effect I'd say, particularly on customer service which was a particular focus for him.
Unfortunately, making recommendations about domain registrars is pretty difficult these days as there are just so many bad ones out there. I used to be General Manager at an ICANN registrar in the UK for some years so I've had the misfortune of having to deal with some really terrible registrars over time.
Online interface wise i've found that most registrars are much of a muchness. Thet all have access to the same registry protocols so there isn't that much room for differentation. The main area that sets registrars apart, be they either ICANN or simple UK tag holders is customer support, and you get what you pay for in that regard.
For example, I personally wouldn't trust the support staff at 123-reg to sit the right way round on a toilet let alone administer tasks relating to important assets such as domain names.
In terms of half decent registrars, DomainMonster are ok and have a reasonable backorder system and in the US, even the lower priced registrars are pretty decent - the likes of Godaddy, etc. But if you have valuable domains you might want to lock them down at specialist registrars with good security and IP knowledge such as Com Laude, MarkMonitor or even NetNames.
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