i want to give it a fresh look and add some members features to it.
i was hoping to design something like this - http://www.amob.com/ with the side background type images but i don't think it will work well at 800x600.
i am not sure who visits charity websites and the stats for the current site are so low they aren't worth looking at.
i suppose i will do that, make everybody happy

i will probably do what wickham said and try to stick to 780px width which i think is the maximum you can go without scrolling side ways on 800x600.
i can't beleive people still use it, it is titchy lol.
i always run full screen for a web browser, word docs etc. but then i have two screens so i can have more showing at once whereas if you only have one, full screen can be a bit awkward.
Macs can handel full screen apps. i regularly do use full screen apps, such as photoshop, dreamweaver and remote desk control.
BUT macs are designed to do more than one thing at once, which is easier when things arn't full screen. at the present time, i am surfing the net, watching TV, on MSN, on skype amd reading e-mails.
i don't think it is down to a mac or windows or even linux to whether you open things in full screen but down to how big your screen is. obviously the larger the screen the less chance you would need to make something full screen but if you have a 15" or 14" then you would need it full screen.
p.s. i so badly want a mac!
sincerely, almost everyone has a 1024*768 resolution on its monitor. above all, a lot of people is buying lcd monitors with BIGGER resolutions. what's the point you may ask. well, if you build a website thinked for 800 * 600, those with a resolution like 1280 * 1024 won't be able to see a goddamn thing!
so, imho, you should just consider 1024*768 and over. even the worst computer today has at least a 17" monitor so i think you should go this way. that's how i do it and nobody ever told me that my website is too big

it is true that the majority have 1024x768 screens or even bigger but still 17% use 800x600 - http://www.w3schools.com/browsers/browsers_stats.asp
that is nearly 1 in five people which is very high!
i think liquid sites are the best but i still design all business sites to a max width of 780px;