Old parquet floors are beautiful looking but can be a pain to repair, maintain, and clean. We've found that they are nice when you have just one damaged 2x8" strip. It can simply be removed and replaced in very small areas. We've also become very handy with a finish nailer, used for securing random loose slats into place.
The web has a few good resources for old parquet owners:
Here's a tutorial on how to repair parquet flooring at How Stuff Works.
It can be useful to keep a small stock of old parquet flooring on hand. Check architectural salvage shops like Olde Good Things. Replacing small areas of damaged flooring with salvaged parquet looks much better than a patchwork of old and new.
This parquet floor brush by Miele is made specifically for vacuuming parquet flooring. Vacuuming is preferred to wet mopping because moisture is easily trapped in the many joints of parquet floors.
Check out this history of parquet flooring at The Parquet House for a little backup info.