Tablets are a new product category and still in its infancy. So far they are aimed at becoming netbook replacements; usually maximizing content consumption but some have content creation ability. After some searching, here are the tablets worth considering:

$99 Web Special - ZTE V9 Optus (7" WVGA resistive touch, 600MHz cpu, 3,400mAh, CMod7, Telephone+3G)
$165 - The Superpad2 (the current craplet king)
$200 - Nook Colour (lots of love at xda)
$300 - Original 7" Samsung Galaxy Tab (bang for buck)
$300 - Advent Vega/Viewsonic G-tablet (was my favourite)
$400 - Malata Zpad/Woow! The One (predates iPad2)
$400 - ASUS Transformer (now favourite) + $150 LaptopDock
$490 - New Samsung Galaxy Tab 8.9 (brilliant)
$500 - New Samsung Galaxy Tab 10.1 (great)
$500 - RIM Playbook (many strengths and many disadvantages)
$500 - Apple iPad (needs no introduction)
$600 - iPad 2 (double the capability of the original)
$650 - Exo-PC (mediocre tablet, but has good touch-software)
$800 - HP Slate 500 (best x86 with 2 major flaws= small battery and no touch software)

We will see:
-LG G-slate (8.9" perfect size, 3D cameras)
-Lenovo IdeaPad K1 (consumer aimed, average features, 3D front and rear cameras)
-Lenovo ThinkPad Tablet (corporate aimed, native pen-support, leather keyboard case and trackpoint, USB-host)

edit: July '11 Update!!!!