under 50K you also get compaq presario v6604AU and such. Upgrading to 2GB RAM would mean it might come to 40K + extended warranty at around 8K (for three years instead of usual 1 year and is worth it).
Depends on what you wish to use (software I mean).
Based on my assumption, image analysis would be the most important requirement. NIH image analysis for MAC is available.
ImageJ (platform independent) is available anyway which is similar to NIH image analysis software.
Both are free, of course!
I would go for some athlon based processor with good graphics support (nvidia, geforce). Regarding Operating system, it is at your convenience.
If you mention what is your software requirement/support required, I might be able to give some ideas.
I would still prefer to go over with linux distributions and run those that need windows environment under wine (a windows emulator under linux). I don't like it but tried a few software for 'trial sake' and it works quite decent!
So some good linux distribution (ubuntu is good for a beginner/advanced linux user). OpenOffice is good for most presentation purposes too! The problem being some effects/fonts/layouts might come distorted if they were created in MS-Office package and opened using openoffice. We can export as ppt presentation from openoffice and it works decently well that way. It is the other way compatibility that is troublesome at times (not always!)
Scribus - a good typesetting software for thesis/publications
Bibus Bibiography - a good reference insert tool compatible with Ms-Office (tried with office xp) and openoffice. Bibus also has a cool pubmed search features. Once we get the hang of it, we might be more comfortable.
My laptop came with vista... while experimenting with ubuntu installation, I (my error of course!!!!) formatted the main drive and lost vista. Lucky for me, my recovery disk creation had failed earlier! I was left with just two choices- go to service center and get it re-installed or go for ubuntu all over! I decided to do the latter and I have not many regrets. Atleast I am safe from the internet worms and viruses.
Of course, if you are hesitant to be so 'risk taking' there is a "wubi" installation though it uses ubuntu almost one version earlier but installs within a folder within windows (c:/wubi/). And you have the option to uninstall it and the folder gets deleted without any damage to any windows elements.
You can also dual boot or even triple boot or quadra or penta boot (no limits of course!) with windows vista, ubuntu, other OS etc; But you will have to weigh the proper method and try it lest something messes up. er.... I guess I am ranting too much, if you have any specific question, please raise it. I'd try to answer them to my best.