How to find elements using xpath contains class?

have tested an ExtJS application. Most of the page element attributes are dynamic. They change not only when you add a new user or something, they change every time when you open the application. I have found the xpath expressions I get from the tools (Firebug etc.) are not very useful. Here is why:

• hard to read
  
• break easily
  
• hard to debug
  

What I do instead, is rather to spend time looking at the HTML and identify possible unique attributes that are not dynamic and come up with my own expressions. If none of the attributes are static for a certain element, use any other element on the page that does have static attributes with the parent/child/sibling relations to locate.

I often use "xpath contains class", but there are more. Here are some examples:
multiple condition: //div[@class='bubble-title' and contains(text(), 'Cover')]
partial match: //span[contains(text(), 'Assign Rate')]
starts-with: //input[starts-with(@id,'reportcombo')]
value has spaces: //div[./div/div[normalise-space(.)='More Actions...']]
sibling: //td[.='LoadType']/following-sibling::td[1]/select"
more complex: //td[contains(normalise-space(@class), 'actual cell cell-row-lines saj-special x-grid-row-collapse')]