Of even greater importance is the information on the reference page . Where and how you spend your time marketing your site should make allowances for and be based upon the information on the reference page. The summary uses the title and meta tag description which IMHO improves the summaries. I found that plural searches were easiest to manipulate results quite possibly because AJ isn't plural sensitive they seemed to return the same results for plural or singular. LookSmart is also in the mix for a search using singular and plural to some extent but not near as much.
Titles are more important now as well.
If you are optimizing for plural sensitivity use the same sensitivity in the title, meta etc. This has been a known booster on WebCrawler for quite some time. To summarize I have found that this engine is now easier to manipulate especially if you are listed on Ask Jeeves and LookSmart. IMHO excite should be low on your priorities because where it once was being accessed by a few other engines for results these engines are not very important anymore. WebCrawler once was important but a stale database has led to it being used far less than in the past.