The next few weeks will have much to do with the outcome in Texas. Particularly if there's a clear momentum on Obama's side, he may be able to sweep to victory here. But there are some big obstacles.
First, of course, consider the Democratic Strongholds in Texas. The entire border and Rio Grande valley, up to around San Antonio, are dominated by the Hispanic vote. Despite some recent news to the contrary, Hilary still has an edge, if only in name recognition. Important organizations such as LULAC and MALDEF have yet to endorse either (interestingly, MALDEF will be honoring Ted Kennedy on Feb 28). They may stay out of it until the general.
Second, the other Democratic strongholds are the interior urban areas of Houston, Dallas, and most of Austin. Dallas and Houston do have sizeable minority populations, both Hispanic and African American. But Hilary has an important ally in Houston: former mayor Bob Lanier, who served during the Clinton presidency, and hosted the first couple at least once. That puts powerful connections at Hilary's disposal that could offset Obama's push here.