Let's start by looking at Sherman's Trade History:

7/2/09 - Smyth for Quincey, Preissing and 5th round pick (Walker)
Push - Up until this point, LA won this trade, but now that Smyth is back with the Oil for a 4th liner and a 7th round pick, I've got this as a push.  Quincey, of course is still with the Avs - and had a so-so 09-10 and then a bad 10-11 (1 assist in 21 games) before he got hurt when he "checked" Ovi in Washington.  If Quincey bounces back, the better this trade is moving forward.  

3/3/10 - Wolski for Mueller and Porter
Push - Wolski crashed and burned in Phoenix and was moved for Michal Rozsival.  If you're Phoenix, you would have never moved Mueller and Porter for Rozsival.  However, Mueller's NHL future is dicey at best given his concussion history.  This is a clear win for Sherms if Mueller stays healthy this season.

3/3/10 - McNicoll and 6th round pick (Stahl) for Yelle and Reed
Win - Yelle was brought over for two minor league players and helped the Avs get into the 2010 Playoffs.  The Avs even got a minor league player back.  

6/17/10 - Hensick for Talbot
Lean Lose - While TJ Hensick needed to be moved out, moving a younger boarderline NHL / AHL player for an older career AHL isn't enough return.

6/28/10 - 4th round 2012 for Winnik
Win - A 4th round pick in two years for your team's best defensive forward?  Home run.

11/11/10 - Bournival for O'Byrne
Lean Win - We won't know how this trade really looks until Bournival develops, but O'Byrne was brought in to fill a team need and he did that and was re-signed. 

11/29/10 - Cohen for Hunwick
Lose - Moving a 2nd round pick for a NHL player who helps you now would usually be a push, at least in the short term.  This is a clear loss because Hunwick was the worst player on a really bad team last season.  

11/30/10 - Hannan for Fleischmann
Push - Hannan was a solid player for the Caps last season and Flash was an outstanding player for the Avs last season until he was forced out due to health issues.  Both players became UFAs on 7/1.

2/18/11 - Anderson for Elloitt
Lose - The Sens got a starting goalie, the Avs got 2 wins in 12 games from Elliott before completely starting over in goal.  This isn't enough return - awful trade.

2/19/11 - Stewart, Shattenkirk and 2nd round (Rattie) for Johnson, McClemment and 1st round (Siemens)
Lean Lose - The pieces involved are so young and so talented that its going to take a few years to really understand this deal.  That being said, St Louis 3 players that could become an elite player, and the Avs have only 2 - McClemment is a career bottom six forward - so I'm putting this at lean lose.

6/24/11 - Liles for 2nd round (2012)
Lose - Ok - I know this is a salary dump, but why make the trade when this pick isn't until 2012?  Liles could have certainly helped Elliott and Barrie in camp this Sept and Liles return value would have only improved the longer his awful contract ticked down.  You've now moved Liles for nothing until June 2012.

7/1/11 - 1st round (2012), 2nd round (2012 or 13) for Varlamov
Lean Lose - A whole lot has been written about this trade, but the bottom line is this: If Varlamov becomes a star goaltender who takes the Avs to deep playoffs multiple times and lifts a certain cup above his head at some point, no one who will ever question the value.  Needless to say, that's a big 'if'.  With the signing of Vokoun, the Caps have now made it clear that they weren't believers - at least not in the short term.

So to recap - Thats 6 bad deals to 3 good deals.  Even worse, the last 4 deals, all involving key NHL players, have either already proven to be awful deals (Andy / Liles) or are questionable gambles at best.  
However, all of this is completely academic if the Avs do one thing: win.  Did the Avs "win" the Nolan / Ozolinsh trade?  A young 1st line center for an offensive defenseman?  You'd say no, unless you begin to consider that the Avs would have never won the Cup in 96 without Ozo.  Its ok to overpay to bring in the key players you don't have - the pieces you need to win.  Let's hope Johnson and Varlamov prove to be those pieces.