I started with playing AD&D 1st.ed.
After that I joined a group playing D&D (the five-boxed set) but didn't find it to my liking.
When I started DMing, I used AD&D 1st.ed. which I continued to use until the last Dark Sun supplement came out.
Then I paused for a while until 3.0 came out. When I started my current campaign 3.5 arrived, and I immediately switched.
Now, I'm going to finish my current campaign and (depending on how long it takes) possibly start anothe one using 3.5 (Shackled City).
I'm definitely going to buy the 4th.ed. PHB as soon as it's available. I cannot say yet, if or when I am going to upgrade.