I imagine that most people agree that 'regex' is better than 'regexp' when choosing an abbreviated word for 'regular expression'. It's just easier to articulate without that troublesome letter p. However, it still leaves pronunciation of the letter g open to debate.
I think the letter g should be soft, not hard. Or, via a pronunciation guide, it should be /réjeks/, not /régeks/.
The intent is that it should be easy to pronounce, right? Well, to my palate, the soft g is easier and rolls of the tongue better than a hard g. The hard g causes a halt that seems a bit akin to a stammer.
-Wayne