I would reccomend you definitely get 2001 versus 2000i or 2000i2. The newest proe version called wildfire, which is supposed to be released in March, is structured totally different from 2000i. In release 2001 the structure is sorta half way changed to the new style to ease users into this method. In the end modeling will be faster with a lot less menus clicks per operation.
In summary, anything learned on the older stuff will be outdated quite soon and have little or no use to you on the newer software .