It is nice to have a list with top extensions to consider when you start a Magento store. Since Magento Connect now has 2450+ extensions I can imagine it's hard for Magento newbies to get started. But instead of making my own list or referring you to other top lists (there are many out there) I thought it would be nice to do some meta research to create the 'ultimate' Magento extension list.
What I did was quite simple: I collected all Top X Magento lists I could find (7 to be exact). Every time an extensions is listed I gave it one point. In the end I counted the points for every extension and the extensions with the most points ended up in my 'Ultimate Magento Extensions List'.
Here's an overview of 'Top X' lists containing Magento Extensions.
Most of the 'Top X' extension lists I found listed the extensions in no particular order so it wasn't quite useful to assign points based on the positions in the several list.
I based my research on previously published Top X lists on other blogs which means that the list is biased towards older extensions. Older extensions have been available for a longer period so more people will have had the chance to come in contact with them and put them in a Top X list. I couldn't think of an easy way to compensate for this so I left it this way. I did however only used lists that had a maximum age of 1 year (published between July 1st 2009 and now).
Since most lists only contain free extensions (I only found one list including commercial ones) I only included free extensions.
I only looked at General list of extensions, lists on a particular subset of extensions (such as 'themes') are ignored.
Some website will have more 'authority' then others. I'm not the one to judge so no compensation for this.
I have listed my source Top X lists at the bottom of my post.
Recently I've seen some (often absolute) statements going around, generally in the line of "open source commerce platforms are a terrible idea". Now of course different solutions always have different pros and cons.
A hierarchy of evidence (or levels of evidence) is a heuristic used to rank the relative strength of results obtained from scientific research. I've created a version of this chart/pyramid applied to CRO which you can see below. It contains the options we have as optimizers and tools and methods we often use to gather data.