Pcpartpicker.com is a website that (for the Canadian site) connects to the databases of Amazon Canada, DirectCanada, Logitech Canada, Memory Express, Newegg Canada, TigerDirect Canada, and Vuugo to help you build a computer. It is available for Australia, Canada, Germany, France, Italy, Spain, the US, and the UK. You choose the parts you want and it tells you the price from the merchants (including shipping), any promo price (rebate), and if any incompatibilities between the chosen parts are found. You can save the parts list in plain text, BBCode Markup, or Reddit Markup formats and you can send a link to the parts list to someone else or yourself.
Basic specifications for each part and a total estimated wattage for the list are available. Prices include shipping and if you create an account, you can enter a taxation rate for specified merchants and the price will include tax. You can choose to watch pricing from specified merchants and pricing trends and alerts are available. You can also create and maintain an inventory. There are forums and builds posted by users can be filtered by part types.
This is a wonderful site for a hobbyist who wants to build their own computer or for a small computer repair/ building business. One could even check for incompatibilities for replacements parts on the site - so long as the parts are being sold at the time. There are far more features on this site than my quick review includes - I spent an hour on it and feel like I've only scratched the surface of it.
There are a few things I hope that they will change. Parts bundles from some merchants were not included at the time this was written, NCIX.com was a major merchant not included, and because shipping is calculated on each item, the shipping cost may be higher than the merchant's charges if the items are bought as one order.
This is a great site and I look forward to exploring it further. I've a customer who is thinking about a new computer...