There are some sitcoms that required "growing up" before they became really good - and Friends is one of those. Early seasons had distracting gimmicks like monkeys and triplets. Later seasons relied on the performances and writing and were better as a result. Season 7 is a solid season all the way through, with the underlying theme of preparation for Monica and Chandler's wedding appearing in most of the episodes. Thus, the entire season has a narrative flow of sorts, but every episode is still stand-alone and watchable by itself.
Other reviews have listed the entire set of shows, so there is no need for me to repeat that. Some others have mentioned that the season is somewhat bland. Perhaps this is most true for those viewers invested primarily in the Rachel-Ross Axis, especially in the light of the upcoming Season 8 that re-introduces that entire storyline (through Rachel's pregnancy). I, for one, do not miss it. There are plenty of "soap-opera moments" in this season, but I prefer such moments to be centred on the soundstage where Joey is filming "Days of Our Lives".
All in all, it is a solid and very funny season. There are lots of guest stars - a personal favourite is Susan Sarandon as a soap opera queen. The box set is exactly what you'd expect if you've bought previous seasons of the show - there are a few commentaries (which often have a few neat tidbits but which also tend to cheerleading at times), there is a little quiz, and so on. However, the best part of having the show on DVD is to be able to watch it uncut and without advertisements. Friends is also one of those shows that improves when you see the episodes together - the underlying comraderie and warmth of the cast is emphasized, and it makes the inside runnning jokes funnier.