I don't know much about SEO, but was it ever really a question of the engines? My main concern has always been that .com (and its country-code analogues) is user-friendlier; not only do users instinctively look for companyname.com but some of the alternatives don't look like domain names ("visit us at metro.museum"), and others (myself included) are somewhat wary of .cc, .to, and other cheap variants that we have come to associate with hobby sites or low-cost/low-quality/spammy-looking gateways and fly-by-night garage firms.
Does this mean that if there was a scenario where a page from a .info or a .net or a .uk.com was equally well optimised as compared to a page from a .com the former would not be 'penalised' because of its use of one of these domains?
For example, if the .info (or others) was hosted in the UK would it compete equally with a .com in international searches?
Conversely, would a UK hosted .info be ranked lower than a UK hosted .co.uk in a country specific search?