Here are a few of the astro places I visit on the web:
Retailers
First Light Optics – Great service and good stock.
Telescope House – Venerable! Their promotions are worth a look as are their emailed newsletters.
365 Astronomy – Zoltan now sells a huge range of kit including useful knobs and widgets.
Harrison Telescopes – Definitely worth a chat, no hard sell.
Manufacturers
William Optics – A superb blend of form and function.
Skywatcher – Don’t knock it ’til you’ve tried it. Their ED refractors offer legendary good value.
Vixen – My first decent scope was a 80mm achromat Vixen sitting atop a Great Polaris mount. I’m still looking for it on eBay! Now a new incarnation has arrived in the form of the Vixen Advanced Polaris (AP) mount.
iOptron – The Skytracker is a new addition.
Reviews and Opinion
UK Astro Imaging Forum – An excellent place to share images and knowledge.
Stargazers Lounge – In case someone else has asked your question already.
Astronomy Now – The astro magazine that keeps getting better.
Cloudy Nights – A huge range of information on scopes and accessories.
Astronomy for Beginners – A great resource site containing Astro News, Reviews and Images.
Software
Startrails – This excellent freeware program stacks star trail images, without the background sky becoming too bright.
PIPP – Flexible Planetary Imaging software, which is brilliant for aligning frames where the target is moving around.