Houston area since 87.
I wouldn't recommend Pasadena, that part of the metro area is where the petrochemical plants and refineries are concentrated.
1) fits that bill. We had a freak snow storm for Christmas. I think last time I saw snow here was 6-7 years ago. I have the AC running this week.
2) no knowledge about scuba or Guam, but suspect you'll want easy access to Galveston. Check into Pearland, Friendswood and areas on I 45 south of beltway 8.
3) Houses in my neighborhood go for [link|http://www.pioneerhomes.com/commselect.aspx?psCode=H53|$110-220]. I live 20 miles south of downtown, easy access to downtown, medical center, Galleria(uptown). Houston's [link|http://webadv.chron.com/ads/ads_a/adsite/comparisons.html|cost-of-living index is 10% below the nationwide average, ... housing costs 21% below the average.]
4) The city proper is the 4th largest city in the states, largest in Texas. We're [link|http://geography.about.com/library/weekly/aa122099c.htm|10th] when concidering the "metro" area, right behind Dallas/Forth Worth.
5) Humidity is the problem, not the heat. July-August is probably the worst time of year to move here :-)