Does Google penalize sites on "commercial" country code domains such as .me or .tv?

There are no penalties or preferences given for TLDs in google.com. All TLDs are treated equally in a google.com web search.

However, TLDs do affect your search results for country specific searches. For example, a .me or .tv domain will not rank as well as a .us website in a google.us web search. Also, a .co.uk site will rank better then a .us site in a google.co.uk search. This is because country specific searches give precedence to local websites.

So if you are targeting a specific country or region, try to use the TLD for that country or region. If not then the TLD does not make a difference.

In short: no, Google does not penalize .me or .tv sites by default.

Google would generally treat .me and .tv domains the same as .com. They're all seen as generic TLDs (gTLDs), so they are not country-specific by default (technically, .me and .tv are ccTLDs, but since they're used so widely, Google treats them as gTLDs).

.co.uk is a bit different - it's a ccTLD, so it's country-specific. For those, it's possible that they are shown a bit higher in the local search results in the UK. However, you can achieve the same effect by using Google Webmaster Tools' geotargeting feature. More on that is at http://googlewebmastercentral.blogspot.com/2010/03/working-with-multi-regional-websites.html.

For other search engines, it's probable that .me & .tv are also seen as gTLDs, but I'm not 100% certain (these things can change over time). Also, in general, unless you can specify geotargeting with them, they will use the server's location for geotargeting of gTLDs - so if you have a .com website hosted in the UK, it's probable that they will use that as a signal that you are trying to target the UK.