FREE IMAGE EDITOR :: PAINT.NET
In my opinion the best free image editor: easy to use, light-weight, full of features for your editing needs (including layers), constantly updated, etc.; these days I do everything with Photoshop, but I've used Paint.NET for years to make quick edits to my images. The only con is that it's a Windows-only program and doesn't run on Macs but, aside from that, I definitely recommend it.
FREE FTP CLIENT:: COFFEECUP FREE FTP
The best free FTP client for Windows; unlike many free FTP clients, there is no limit to the number of sites you can add. The UI is very clear and has no redundant buttons, and there is also the option to edit your pages directly from inside the program. The main difference with the paid version is that the latter gets update a bit more frequently, otherwise they are equally valid. Definitely a recommended program.
FREE HTML/CSS/PHP EDITOR :: RJ TEXTED
Probably the best free editor for Windows: it supports PHP, HTML, CSS, Java and other several languages; the interface in my opinion is better than several paid editors out there, with menu sections for each language and plenty of feature in each to make your page and honey your web developping skills. It also has an integrated FTP client and file manager, along with a powerful preview tool; absolutely recommended.
FREE MAC IMAGE EDITOR :: GIMP EDITOR
Best free editor for Mac; I personally think that striving so much to compete with Photoshop made GIMP come out bloated, confused and (for free software) way heavy, but still it's undeniably an excellent free editor - most likely the best one for Mac - with all the features you may need to edit your photos and images.
FREE FTP CLIENT:: FIRE FTP
This is not a real client, meaning you don't install it on your computer, but a Mozilla Firefox add-on/extension; this means it works on both Windows and Mac...and the best free client for the latter. The interface is easier to use and understand than that of most paid clients, with all the options and features you need to manage and upload things to your site. Absolutely recommended.
FREE HTML/CSS/PHP EDITOR :: KOMODO EDIT
Probably the best free editor for Mac OS X: it has code highlightning for PHP, HTML, CSS, Java and other several languages; the interface in my opinion is as valid as some paid editors for Mac, with a quite minimalistic yet fully-featured menu for all your coding and/or web-developping needs. The preview tool is not excellent and there is no integrated FTP, but it's still a very good editor for your Mac computers.