Speaking of the large number of great new costume-related books that have been, or will be, published this year, I'd like to mention one that may be more interesting to any male readers I might have:
Sumner, Graham. Roman Military Dress. The History Press (July 1, 2009). ISBN: 0752445766. ISBN-13: 978-0752445762.
I got a copy of this book this summer as a present for a friend who paints military miniatures, so I got to flip through it. It is chockful of lovely illustrations (both reconstruction-type drawings and pictures of actual period art and artifacts). Sumner wrote the Osprey books on Roman military costume, and this volume clearly draws on those, but appears to add extra material as well. Best of all, it's in paperback format and relatively inexpensive; Amazon.com is selling it for $25 USD.
I've added it to my wish list, and I think you should consider getting it if you have a serious interest in the Roman military or Roman culture in general.