I would avoid later works by Digby-Smith ... he is notorious for being inaccurate.
Austerlitz: 1805 by Robert Goetz on the other hand is an outstanding read. He has a nice order of battle in the back of his book. He also did all of the maps on his own as publishers are really stinky about wanting to pay for them.
More good reading is the entire series on the 1809 campaign by John Gill. Also his book "With Eagles to Glory" about the Confederation of the Rhine forces that fought in 1809 is a classic as well.
Others?
Marengo and Hohenlinden by James Arnold - NICE OB info and maps too. Hohenlinden is one of the least written about battles for its size.
The Road to Rivoli by Boycott-Brown - an account of the entire 1796-97 campaign. Really good book and has nice maps. OB info is given as well on a higher level but he gives info on the units in each command as you read the text.
For a nice overview of the Peninsular you can get Julian Paget's book on the Peninsular War. He goes over the campaigns twice. Once from a higher level and then from a battle level. Also this atlas is VERY nice and comes with a slipcase:
http://www.amazon.com/Peninsular-War-At ... 733&sr=8-1You can get it from one of the Sellers for about 30 bucks and save on cost. I got this one earlier this year and it covers the battles of the Spanish army too unlike most English books on the conflict in Spain and Portugal.
That should keep you for some time!

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Generalfeldmarschall Wilhelm Prinz Peters von Dennewitz
3. Husaren-Regiment, Reserve-Kavallerie, Preußischen Armee-Korps
Honarary CO of Garde-Ulanen Regiment, Garde-Grenadier Kavallerie
NWC Founding Member
For Club Games: I prefer the Single Phase mode of play. I prefer to play with the following options
OFF:
MDF, VP4LC, NRO, MTD, CMR, PR, MIM, NDM, OMR (ver 4.07)