Recommended

Premium Managed WordPress Hosting

WP Engine : For higher traffic WordPress sites with greater performance demands, we recommend the excellent WP Engine as the premier provider of managed WordPress hosting.  WP Engine provides expert-level WordPress hosting and support.  They are currently offering two months of free hosting with one year of prepaid hosting and their 60-day risk-free trial offer. Check them out!

Basic Web Hosting

BlueHost : For those on a tighter budget without high-performance WordPress server needs, I recommend checking out BlueHost as a good option.

WordPress Training

WP Apprentice : Learn WordPress quickly from their extensive collection of in-depth video tutorials. On-demand and very affordable WordPress training at your own pace. Perfect for beginners.

Domain Registrar

iWantMyName.com : Tired of ads, up-sells, and lacking customer support at the big domain name registrars? Try iWantMyName.com.

Event Registration

EventEspresso.com : Want to host and manage event registration on your WordPress site?  Try EventEspresso.  It fully delivers where the other options fall short.

WordPress Themes

There are a lot of really nice themes and frameworks out there.  Some of my favorites include WooThemes for their robust feature set and well-designed code, and VivaThemes for their simplicity and elegance.  StudioPress and DevPress also both make really solid themes, and  ThemeForest has innumerable WordPress themes from developers around the world.

E-Commerce

This is a pretty big topic and often coming up with the right solution involved a thorough discussion and understanding of the business. However, for a good all-around free solution I will often look at WooCommerce, and for a more robust hosted third-party solution I will recommend checking out BigCommerce.

Site Security

Securi Security provides excellent services when it comes to site security and WordPress.  If your site has been hacked or if you are experiencing other security related issues with your WordPress website, you might want to check with them first.