First, who exactly was Vesper working for? I got the impression that she did fall for Bond when she removed the necklace that had been holding onto the past. Her boyfriend was being held captive, but by which group? There was mention made about her having saved Bond's life, but what kept her from being saved at the end? This was all very confusing.

Also, Bond was under the impression that Mathis was the informant to LeChiffre because of the bluff comment. But couldn't Vesper had been the one to have told him. When Vesper gets the supposed call from Mathis, couldn't this had been LeChiffre? Much is made to believe Mathis' guilt, but I don't know if that guilt is correctly placed or if we are just supposed to believe it.

Lastly, on the phone was White's number. Who sent it?

Vesper worked for the british, officially. Hard to say when she began working for the shadowy organization in the background. Did they kidnap her boyfriend out of the gate as insurance in case Bond won or after Bond won? Anybody could have beat Le Chiffre so maybe it happened after Bond won. I do believe she was in on the capture of Bond and was faking being tortured in the other room. I also believe the hospital where Bond was recovering was a SPECTRE(or whoever) facility. Mathis is at the faclity so he definately was a bad guy.
Le Chiffre was an underling of this bigger organization(like Largo in Thunderball). The guys Bond fights at the end in the collapsing building work for this organization, Le Chiffre is kaput and out of the picture by then. LeChiffre was probably killed either because of his planning to go for the protection for info offer or just out of principal because the organization doesn't tolerate failure.
As for Vesper's suicide. I think it was because she couldn't live with the fact that Bond knew she had betrayed him. I understood it that White called Vesper in the hotel room and Bond got his number off her phone.
There are a lot of things about the movie you think about later and wish you had the dvd to go back and check out.

I had the same questions about Vesper. At one point did she start having her own agenda? I'm sure she was legit at some point, but at what particular point was her boyfriend kidnapped? It would only make sense that her boyfriend was captured after Bond won the money. Otherwise, what would she really have to offer to anybody?
I never thought about the hospital being a SPECTRE facility, but that would make sense. Of course, that is where her character does a 360 from "tolerating" Bond to being in love with him. This may have had to do with her now having to get the money to release said boyfriend. But his feelings towards her may have actually won her over, but she still had to take care of the money aspect.
I wish that there was more development with Vesper's character. I believe that may have given us more understanding as to why she would rather die than have Bond rescue her. Of course, maybe her past had a number of misfortunes, and she'd rather die with the positive memories of Bond that have negative ones. I'm probably overthinking her death, but it certainly isn't normal for someone to drown themselves, right?

What leads me to believe the hospital is run by the villians is Bond seems to be out of contact with M/London. To much shady stuff happens there for me to think it could happen under the nose of the British. I'd have to see it again but pretty sure the two guys who tok out Mathis were bad guys and waited until Mathis was out of Bond's sight to get him so Bond wouldn't see it.

M asks Bond of he thinks Mathis should be released after Vesper is dead. This implies that MI6 did indeed have Mathis in custody.