tedster - 7:02 pm on Jul 14, 2011 (gmt 0) [edited by: tedster at 3:23 am (utc) on Jul 15, 2011]
"Spanish" speakers in the US are predominantly Latino - from Mexico (great majority), Puerto Rico, Columia, etc. A ccTLD from Spain like .es is not really in the picture as far as I know. Google.com is an international domain name and handles non-English searches just fine.
I'd focus on google.com (or google.com.mx as a secondary) and use a .com domain name of your own. And do some intense market research first. The Spanish language as spoken by US Latinos/Hispanics has many variants, and the cultural differences also need your attention. Second generation US Latinos will have different search habits than their parents. And the entire market is more mobile oriented than the US market in general.
BTW, I just recently saw research that Google claims 93% of US-Latino search market.
[edited by: tedster at 3:23 am (utc) on Jul 15, 2011]