I just came in to mention Manhoef and Lawler myself.
I have to give respect to Strikeforce because I might not be watching MMA like I do today if it wasn't for them.
With the exception of UFC 100, which I watched for Bisping/Hendo on the TUF finale, and a few Brock fights I googled, my first real MMA live event I watched was Strikeforce Miami, which was an awesome card and got me really interested. You had Bobby Lashley, whom I knew from wrestling, destroying his opponent in the first. The amazing Robbie Lawler KO over Manhoef, this near 50 year old man, Herchel Walker, looking outstanding in his MMA debut, this freak of nature woman wrecking machine in Cyborg and my future favourite fighter of all time, Nick Diaz win the first Strikeforce belt. I was showing everyone every fight from the card. The former pro wrestler looking great, the amazing KO, the 47 year old man in amazing shape, the woman wrecking machine and then of course Diaz. That card really brought me into being an MMA fan as we didn't have the luxery of having real MMA on TV (except TUF UK/US and BAMMA) up until last year. That event alone probably kept me going in finding streams online to watch the fights etc so I'll remember Strikeforce fondly for that.