I really had to visit the Vista pages to verify I didn't overlook something crucial...
those so-called security issues are all homemade - any flavour of an M$ OS suffered from tons of flaws (the more you look, the more you'll find). The (so-called) operating system is an endless mess of a patchwork.
Do you really know what those executable files in your system directory are for, in which sequence and under which circumstances they may be called - and how much stuff is executed behind your back without informing you... ?
take an item as simple as an autostart entry:
at how many locxations and under how many registry entries could it be filed ?
And now this company praises itself for sorting out a few items they carefully messed up themselves ??? LMAO
Since they didn't change the basic concepts you can bet that even more issues will turn up when this thing is going to be used.
Most of what's advertized on the Vista pages regarding network security is far from being OS related...
...and is available as an add-on for other (browser)applications anyway.
Secure internet access for children ? What a bs - you either accept that they will be confronted with some not so romantic aspects of life (and handle it together with them...), or you keep your kids away from a networked computer. That simple.
And once the kiddies get even the slightest suspect they might be 'cheated', they will find a way...
Vista's search function is a copy of Apple's spotlight, as 'Gadgets' is a copy of 'widgets'.
Both are nothing revolutionary and highly questionable in their effectiveness - even the original Apple versions.
Before this supa service is instantiated the drive must be indexed... which does not happen out of the blue or within the blink of an eye...
but I can tell you how Apple's version 'works'...

They've been so smart in their infinite wisdom to ease the transfer of 'your old data' to a new Mac by simply connecting the 'previous machine' with a Firewire cable.
So far, so good, it's easy - hold the proper button and your old trusty ex-disk shows up on the desktop of the new machine, ready to be copied... ready ???
LOL - Spotlight will first try to index all your 0.5 million files - and lock the machine for an hour or so...
I've never been able to (reliably) interupt the process or to tell the bloody program it should get off the FireWire port or anything that's mounted there. The function might exist deeply burried in the ix-ish core...
I may add that our picture archive server sends gigabytes of tif files over the network just to create those crappy icons (which noone needs as perfect thumbnails exist anyway) for the desktop file of any remote machine that's mounting it - at least that's my impression. Again I may be able to configure that if I read long enough.
For that same picture server a few (old, mac-syntax, illegal chars) files wouldn't copy, so I used Spotlight's ingeneous full text retrieval to sort out the suspects beforehand. Do I really have to mention the ton of false results because the f*cking char was looked up anywhere in the file ? Yes, again you can configure it manually...
Of course a few 'false' candidates slipped through, and whaddaya think ? It fails after 17k files outof 53k even though it had done a full pre-check, leaving no information about what has been copied, what failed and what's on schedule still.
Yes of course, here we go again - I could write a shell script for exactly that task...
WTF is this GUI thingy for, if I have to return to DOSmania and the commandline anyway ? THAT is a true Denial_Of_Service.
Apple did a marvellous job in hiding the unix part of MacOSX, but they simply loop back 25 years ignoring their own achievements in user-friendly interface design.
No question, if I'd spent those years shell-scripting, you'd have to call me a whizz for sure today
but please don't come and tell me that M$Soft did all of the afforementioned in a smarter way 
those features all read great in keynotes (from people used to delegate those dirty tasks)... I've taken some Apple examples, but I really don't think it's much different under Vista
nevertheless there
is one serious reason for Vista, and it's called dotNetThree, supposed to replace the Win32 call api
if all your favourite apps work perfectly under x86-unix (with the help of WINE or Crossover), why should you run an 'unsafe' environment like Windows anyway ?

Not to forget virtualization that may re-vitalize old server systems on new hardware.
And that makes Vista nothing but a lame attempt to secure a monopoly - and get a bit of the home entertainment cake so neatly i-ced by Apple's i-featuritis
cheers, Tom