Listed below are all the pros/cons I can think of for Skyrim at this time.
Keep in mind that my pros/cons list is in relation to Oblivion, as I am a big Oblivion fan, as are many who will buy Skyrim.
1- More options for travel (two ways to fast travel in addition to walking/riding a horse)
2- You can make your own weapons/armor and upgrade them
3- Radiant Story ensures different experiences every time based on how you play
5- Dragons! Dragons! Dragons!
6- More variety for environments than in Oblivion
7- Dual wielding for weapons and magick
8- Dragon shouts
9- More, bigger cities than in Oblivion
10- Dynamic non-lethal barfights
11- More robust, timing based blocking system
12- Torches can be used as weapons
13- Improved bow combat than in Oblivion
14- Improved Radiant A.I.
15- You can hire mercenaries (companions)
16- Much more detailed environments, environmental features and weather effects than in Oblivion
17- More voice actors than in Oblivion (70)
18- More character creation/customization options
1- Potentially streamlined combat compared to Oblivion
2- Acrobatics and other minor skills removed (everything except health, magicka and stamina)
3- No dodging, rolling or backflipping during combat
4- No weapon/armor degradation
5- Spell creation removed
6- Potentially streamlined armor which may lead to less armor than in Oblivion
7- Potentially less side quests/content than Oblivion