I'm almost 35 so I'm definitely somewhere in the middle. I'm not at all scared of being sidelined by young guys because I do not define myself by current skillset (currently a web developer doing mostly Ruby/Javascript in various forms). What experience has taught me is that being able to program well is an incredibly valuable skill if and only if it is applied to the right problems at the right time. So while some of my skills over time have had an extremely short half-life (Netscape/IE 4 CSS), and some has had an intermediate half-life (HTTP/SSL/web servers) and some promise dividends for years to come (bash, vim, linux sysadministration), the ability to leverage and apply technology to real business problems is something that will always be valuable. It doesn't matter how many genius kids drop out of the ivy league, they have to earn their experience in how to succeed in the business world. Of course, if I am always looking for a job I am subject to ageism, but that is why increasingly I look to put myself in founder/consultant roles rather than simply coder for hire.