Here's an interesting graph on Traderfeed adjusting the S&P500 index for the declining value of the dollar. Taking the declining dollar into account we're still considerably below values in 2000.
How low will the value of the dollar go? Value of dollar vs. major currencies is shown below. Link to Federal Reserve Source
For those of you interested in the value of the dollar, here's a good post on the Big Picture blog. I find the continuing fall of the dollar a very interesting story and relevant to long term investing. Problem is I really don't know what to do about it other than invest in export oriented companies, international companies/stocks, or actually convert dollar denominated cash into other currencies. There are some currency ETFs out there also (here's a good story with links), but I'd rather get my assets into productive assets/equities rather than buy into the increasing spread between the dollar and other world currencies.
Several threads I've been reading discuss the declining value of the dollar, but I haven't seen many that put the value of the US dollar in to a long term perspective.
In an effort to understand what's been happening I went to the Federal Reserve site to get some historical data. The time series below plots the major currencies index. Per the FED site: "The major currencies index is a weighted average of the foreign exchange values of the U.S. dollar against a subset of currencies in the broad index that circulate widely outside the country of issue." 
The dollar is currently at some of the lowest levels seen in over 30 years relative to world currencies.
My next question is how do I protect my portfolio from currency loss like we've seen, particularly if the trend persists? I don't know the answer currently, but it's worth thinking about since relative to world currencies the dollar is worth 22% less today than it was in Dec 2000.
