What is popular this days in WordPress theme trends ?
Trend 1 - Tabbing System
Trend 2 - “Featured” Post Display
Trend 3 - Post Thumbnails
Trend 4 - Cross-Browser Transparency
Trend 5 - Animated Dropdown Menus
Trend 6 - Modal Boxes
Trend 7 - Theme Options Pages
You can see all of those implementations in new WordPress themes that are served to you this days.
If you want to implement those methods to your blog theme read this tutorial: 7 Wordpress Theme Trends & How To Implement Them Yourself.