If Tony had died after he was shot by Junior, whom would have stepped up to the big seat as the new boss?
I would imagine there would have been a lot of in-fighting as Sil, Vito were vieing for the top job, not to mention Paulie
Your thoughts please?

Silvio, no question. For one the Lupertazzi's had done business with him before and their support is needed when taking the reigns of the DiMeos. Silvio would also have the support from some Caporegimes : Bobby Bacala, Chris Moltisanti, and Larry Barese. The Underboss (in name only) Paulie likely would support Silvio.

Boss - Silvio Dante
Underboss - Peter "Paulie Walnuts" Gaultieri
Consigliere - Vito Spatafore (for the time anyway)

But Silvio crumbled under the pressure...and we know of Vito's secret life that was bound to be found out sooner or later (and was), negating him as boss...

Paulie was a follower and not cut out for the job...

Chris might have become Boss after Sil and Vito disqualified themselves, but wouldn't have lasted long because of the drug problem and lack of respect from the Capos...

Bobby, Patsy or Carlo? I don't think so...

Essentially, the DiMeo Crime Family would have been leaderless...

The episodes immediately following "Members Only" explore this what-if.

I agree with Paddy: essentially, without Tony, the "glorified crew" falls apart. The daily stresses of the job have always been there for us to see, but in Tony's absence, we see how others would have reacted.

Paulie's too simple-minded to be a leader of anyone beyond his own one-way ladder of paying packages. He doesn't have the respect of everyone, nor is he able to move with the times. He grew up under Johnny Boy Soprano, and he knows it; he likes a simple life - look at his reluctance to step up as captain at the end of the series.

Bobby was, by the beginning of season 6B, going to be groomed by Tony to form a revised inner circle. At the point of Junior shooting Tony at the beginning of season 6A, though, it wouldn't work. Not enough respect; too selfish, as a result of Janice's money-driven influence.

Vito's a sleazebag; the only one who actually thinks about becoming boss if ("God forbid") anything should happen to Tony. He's the most interesting choice begging exploration for this question; he can throw his weight about (excuse the pun), but rarely does. Ultimately, though, his ambition is undermined by his eventual submission to hierarchy (calling Silvio "skip" in the urinals).

Christopher would never be looked or called upon as leader, whether acting, interim or permanent. Everyone - including Silvio - resents his progress up the hierarchy as Tony's most trusted underling. And the drugs intervention in season 4 pretty much severs all hope for him.

Carlo might have stepped up, but again, the same problems as Paulie: he's ultra-conservative (note his reaction to Vito's homosexuality, and the problem it caused Tony) in a world of increasing political instability and everyday uncertainty. Given the general narrow-mindedness of all others of similar positions, though, he might last at least a while.

Patsy is another interesting choice, because we only really get to know him later on in the series; he's a fascinating character (played by a brilliant actor), but ultimately, not up to taking over. He's at his most effective when playing an instrumental role.

Silvio: he does step up as acting boss, and fails. It's important that Chase shows us this. He cannot deal with the everyday stresses of the job, the torn loyalties, the required objectivity of leadership, the sit-downs, the disputes, the balance with family life.

All of these play a significant part in enhancing our admiration for Tony as a fictional leader. They're what makes the coma episodes so fascinating; it's like asking what would happen in The Simpsons if Homer was killed and permanently written off.

Couldn't have put that last sentence any better, Capo!

Silvio would never had been the boss, he stated that he was more of a "behind the scenes type of guy". Plus he was stressed into an asthma attack when he was acting head.

Boss - Vito Spatafore.
Underboss - Paulie Walnuts.
Consigliere - Sivio Dante.

There would be a definite drop off, but there would be a new boss, successful or not.

Vito wanted the job and would have had NY's support being Phil's cousin.

Then Vito would have ended up like Johnny Boy D'Amato.

Which brings us back to the original question.

Bobby, Patsy and Paulie with Silvio advising all three.

Kinda like the 2 Palermos, Majuri and Vitabile advising in real life.