I agree with dr_st completely. Windows Seven doesn't have many of the new version setbacks that previous windows upgrades had, such as requiring much more memory, so if it wasn't for price, I'd go with Win7, but I think Vista can run just as well in most cases. One of the reasons Vista wasn't accepted is the initial opinion of the user account controls was found to be annoying to most people. This feature was vastly misunderstood, and even if it did bother someone that much, it's an easy matter to disable it, but the benefits it offers were many. In that era there were many websites that were installing malware on a "drive by" basis, without asking for confirmation, or by displaying a false warning. With vista it would refuse to let anything install without redundant warnings at user and admin levels... people hated this, but it was a silly reason to denounce the OS. Driver issues were plenty, but that really wasn't entirely microsofts fault, much of the industry didn't care about writing drivers for old hardware, so it took a wile for the rest of the world to "catch up" to vista. By the time Vista was up and running full speed (about SP1 in my opinion), the word on the street was to downgrade back to XP (very bad advice)
I really do like Vista a lot, and to show my appreciation for this underrated OS, I'm going to offer a $10 discount on a used copy of Vista Business 32 or 64bit. That is an original Vista RTM disc downloaded direct from microsoft (your choice of 32 or 64bit) that has service pack two integrated and a genuine microsoft COA for only $20 shipped (domestic). I have these listed in the marketplace for $30, but I've selected (5) of them to offer to readers of this thread (PM for details). I'm practically giving them away at this price, so the only thing I ask is that you give it a good "road test" and report your findings/opinions for others to benefit from. The Vista Business is the same as the Professional versions of windows, just a different name was used on vista. I also have ultimate, basic, but in much smaller quantities, and XP professional.
As for the tweaks, I have tried many modded versions of windows. There are many traded online that have had a lot of unneeded (bovine excrement) removed, things like indexing of files, a lot of completely redundant apps that no one ever uses, things like that. When Vista ultimate first went RTM, the setup disc used nearly a full DVDr disc, and the 64bit version required dual layer (until sp1 which will fit on a single layer), but the stripped down version I tested fit on a 700mb CDr disc. I didn't find anything missing on it that I would have used, things like "wordpad" for example are completely redundant... if I needed a text editor that bad I could use notepad, but I install OpenOffice on all my systems anyway so wordpad never gets used. Indexing service runs in the background keeping track of all your files so you can search them faster, but the cost is using up precious resources and I don't often need to do searches on my own drive and even if I do, on those rare moments I don't mind waiting a few minutes longer for the search to complete. There are many such things which can be stripped out to make windows "lean n mean", instead of "fat and bloated". For Windows XP, one of my favorite versions was done by a group called "eXPerience", that tweaked all 2000/XP/2003 versions on three levels. Full, Tiny and Micro. Full gives you everything the microsoft version offers but with some enhancements for performance (for example, indexing is disabled but not removed). Tiny is my favorite. The .iso file is about 288mb if I recall correctly, and it installs only the basic OS and optionally lets you decide if you want Internet explorer or windows media player installed. This version will generally run faster using much less ram and is completely legal to use as long as you own a license for the version you're using. The Micro version will run on 64mb of ram and the .iso is well under 100mb in size. I've used it as a secondary operating system for doing repair work by installing on a separate partition along with some recovery software and repair tools. I do admit that this version can be annoying when it comes to getting some hardware to work on it. I got a massive headache getting my wifi to work with it, but this is to be expected when you strip something down this far. In summery, if you have a very old system that and want to make it usable, one of these versions is a great option, and even if you have a fast system but you're into gaming or other resource intensive use like video encoding, then I'd recommend trying one of them. Windows tries to be a "jack of all trades", and ends up becoming so bloated that it turns out to be "master of none". Microsoft even gave up on using Windows as a base for the Xbox in favor of Linux, which is another option for older hardware, but I won't go off topic by discussing linux in this thread.
***Available The ultimate T60/61 frankenpad board, brand new in original sealed IBM box, long thought to be extinct... TuuS ***
*** Just in: New production Hydis 15" UXGA with LED backlight only $69 ***