Oxymorons...

More about Oxymorons:
An oxymoron is a figure of speech that combines two normally contradictory terms. Oxymoron is a Greek term derived from oxy ("sharp") and moros ("dull"). The most common form of oxymoron involves an adjective–noun combination. These are commonly used Oxymorons. We probably never realize that they fall within this category.

45. Act naturally
44. Found missing
43. Resident alien
42. Advanced BASIC
41. Genuine imitation
40. Airline Food
39. Good grief
38. Same difference
37. Almost exactly
36. Government organization
35. Sanitary landfill
34. Alone together
33. Legally drunk
32. Silent scream
31. Living dead
30. Small crowd
29. Business ethics
28. Soft rock
27. Butt head
26. Military intelligence
25. Software documentation
24. New classic
23. Sweet sorrow
22. Child Proof
21. Now then
20. Synthetic natural gas
19. Passive aggression
18. Taped live
17. Clearly misunderstood
16. Peace force
15. Extinct life
14. Temporary tax increase
13. Computer jock
12. Plastic glasses
11. Terribly pleased
10. Computer security
9. Political science
8. Tight slacks
7. Definite maybe
6. Pretty ugly
5. Twelve-ounce pound cake
4. Diet ice cream
3. Working vacation
2. Exact estimate

..And the number 1 oxymoron is

1. Microsoft Works