In a certain number of topics in the Forums I saw some fans saying that Obi-Wan is not very strong in the Force because he didn't feel Windu's and other Jedi death like Yoda did: I'll try to explain this fact.

1. First point Mace's death:

When Mace Windu was killed by Palpatine after Anakin's betrayal Obi-Wan was tryingr to rejoin Commander Cody after Grievous demise so he was concerned to avoid droid fire, he lost his lightsaber , that's the why his feeling told him nothing about Windu( It's undoubted the Yoda is more powerful in the Force but some fan said Obi-Wan wouldn't be able to feel something like that beside the relationship between Yoda and Mace is very strong : the were friends for many years and we saw in AOTC they even madite in the room!)

2. Second point : the Jedi killed by order 66

We have no proof Obi-Wan didn't sense them beside he was the first Jedi to be betrayed and fell in the water so the options are two: He felt their death or he didn't: from its dialouge with Bail it seems he didn't felt their death but there are no profs he felt, at least a distrurbace( he felt a distrurbance in TPM when he was only a padawan so he must had felt a disturbance now that he is a Master). Yoda who is one of the most powerful Jedi ever felt it in details but it doesn't proove Obi-Wan is not powerful in the Force but that Yoda is the most powerful.
By an accurate vision of these scene we can see that Yoda felt the Clones were trying to kill him by he didn't feel for the other Jedi the same "experience" he felt when Mace was killed ( I've seen the movie 5 times and if I can remember right the scene of the picture here tooke place after Mace's death right?).

edit(Jun 23 2005): After have seen the movie 6 times I'm certain Yoda had the same reaction after Mace's death/Anakin turning and during the execution of Order 66