Windows XP Premium Edition 2010 Features:

1.  Transparency & Blur found in Vista/7
2.  Windows Flip 3D
3.  Transparent Start Menu
4.  Start Menu Search
5.  Windows Media Center
6.  Microsoft ClearType
7.  Windows Defender
8.  Windows Media Player 11
9.  Windows Internet Explorer 8
10.Windows Search
11.Favorite Links
12.Speech Recognition
13.Handwriting Recognition with Tablet Support
TOOLS:
a. Snipping Tool
b.Sticky Notes
c.Tablet Input Panel
d.Math Input Panel
e.Windows XP Tablet Experience Pack
f.Microsoft Sudoku Game
g.Inkball Game
h.Windows Journal
14.Mac OS X like dock
15.Windows Live Essentials
16.Windows Vista/7 Games
a.Chess Titans alternative
b.Inkball
c.Sudoku
d.Purble Place
e.Freecell
f.Minesweeper
g.Hearts
h.Shanghai
i.Hold 'Em
k.Solitaire
l.Spider Solitaire
17.Windows Plus! Digital Media Enhancements
18.One-Click bug reporting
19.Windows Sidebar
20.Enhanced mini applets (like Notepad, Paint, Volume Control, etc.)
21.Create additional three desktops
22.Configure ClearType according to your needs.
23.See previews while flipping using Alt + Tab
24.Preview enabled taskbar tooltips
25.Enhanced folder explorer
a.'Breadcrumbs' address bar from Vista/7
b.Tab enabled explorer
c. Favorite Links
26.DirectX 10    NEW!

and many many more features!