BlogEngine 2.5 final release is ready for download, and most anticipated new feature is obviously ability to run multiple blogs on single code base. It's been a top request for a while, so hopefully it'll make lots of people happy. You can read in-depth about it on Ben's blog, I'm not going to repeat it here. Just want to say - don't dismiss it if you only going to run one blog, it can be helpful in many ways. I for one planning on little family "members only" site working as sub-blog and another used as private Wiki. All on the same code base, with single update cycle - can be a time saver.
Another big feature is integration with online gallery that currently will let you install themes from web store to your blog with a button click. This feature is largely experimental and might be responsible for future direction that project will take. We definitely going to see extensions/widgets from online gallery in admin panel in the next version, but potential is so much bigger. I really hope this works out well. If you customizing BlogEngine, consider doing it by creating reusable code so it can be NuGet-packaged and shared with community - sharing is fun :)
BlogEngine also updated to .net 4.0 and made a move to utilize web pages (Razor). Decision was definitely not driven by "cool" factor - after quick evaluation team came to conclusion that Razor is great template engine with clean output and should save time in the long run. Plus there is possibility to take advantage of growing number of HTML helpers that can be used as extensions, sometimes with no modification needed. Sure as with any new technology it requires investment up front, but you have to give some to get some, right? Only new functionality and parts of the site that needed complete refactoring to support new features were coded in Razor, and move in that direction will probably be slow but steady. Don't see web forms support dropped any time soon.
There were few changes to generated HTML output in attempt to address some of the pain-points in building custom themes, specifically in form/comment view. This should give more control and make design tasks a little easier, admittedly more needs to be done. Not much changes to spam protection this time around, which is a good sign - 2.0 got strong tools to fight spam. One small change is turning simple captcha on by default and including it as a another field in the form, so it looks more natural.