My current internet connection is Qwest's DSL at 7mbps. Is that enough to get the most out of Netflix HD, or do I need to upgrade my internet?
In theory, 7mbps should be more than enough for NetFlix, as I think the highest quality NetFlix streams are under 5mbps.
However, that's only part of the story. Keep in mind that most home ISPs quote the speed as "Up to xxx" (with the "up to" being the part many consumers overlook). In essence, you may not get the full speed quoted, because the ISP (technically) never promised that speed (only that the speed might get "up to" that fast).
Also, the internet has more and less busy times of the day (as well as more and less busy days of the week). And the same is also true of the NetFlix servers (i.e. there are times/days when NetFlix is very busy streaming, and less busy times). If you try to stream during those "busy times", you may very well notice a lowering of NetFlix quality even if your link to your ISP doesn't slow down (because the quality of your viewing experience will be controlled by the slowest portion of the link between you and NetFlix, and that slowest portion of the link is not always your personal ISP speeD). For example, even though I have 10mbps DSL (more than enough to get full HD from NetFlix), I sometimes still notice NetFlix slow down to 3 or even 2 dots (SD) during a "busy time" for the internet and/or NetFlix.