I'm going to post more about this on Ghost stuff over in the Ghost thread. That said...
I see a lot of interesting cultural literature and art shifts during this time period. Art and literature tend to reflect the age they are in (duh) so trying to predict what this might be like is interesting.
The Terra government adopted several of the free speech and civil rights portions of the United States government - largely at the insistance of the western powers that be but also because it allowed for the most integration of the previous cultural identities of various world nations. This has lead to a proliferation of culturally relevant artistic commentary as well as the general "brain fluff" that your average individual encounters.
Television:Television is still popular, though there has been a push with the Terra government to provide a variety of mish-mashed references that can be appropriate for all cultures. The result has been somewhat mixed - occasionally working, sometimes getting pulled from the air for being just blatantly stereotyping, and other times falling flat as humor failed to translate across culture. Reality TV has thankfully died out with the advent of space travel, though there was one ill-fated attempt to document the "reality of life aboard an isley ship" that has become somewhat legendary in television cult circles as one of the most attrocious pieces of garbage ever to air. Television by and large has fallen now into one of two categories - popcorn entertainment and educational. Movie channels still offer a diverse variety but general programing tends toward one or the other. Primarily because of...
ITV Televisions most recent sibling and standing for Interactive Television this form of entertainment is a fancier version of today's interactive tv/computer hybrids. Most culturally relevant and political material is posted on Intera-vision - essentially TV with a communication and real-time debate and interactive ability built in. This is a popular medium for debate and political commentary, but also for talk-shows, journalistic news programs that encourage questioning and discussion on relevant current events etc.
Strangely, this has also become a popular medium for sporting events as fans can now interact as if they were in person at the game. Unexpected but "football buddies" no longer even need to be on the same planet.
Movies: While original movies still continue to be made, there was a popular streak in the late 21st century to remake previous "hits" in all it's forms. Jokes still continue that the best Star Wars was number XIV and that the third 3D Godzilla remake was just as campy and terrible as the first movie. CGI technology has advanced to the point where it is not uncommon for entire actors to be computerized and used for films and many serious films are comprised of computer animation.
Painting and 2D art: Obviously these still exist. There has in fact been a resurgance in the so-called "classical arts" as various groups try to maintain cultural integrity in the face of tremendous change. As always, various groups are always railing how these arts are dissapearing while others are railing that they are in fact healthy. The debate continues.
Theater and dance Continues as well, both in simple forms, but also with increased technology. Aerial performances, holograms, and various special effects have become popular, leading again to the age old debate of "flash" versus "quality" in theatrical performance.
Literature: Much to the lament of "true readers" everywhere, paper books are a rareity and are typically left dirt-side in space travel due to the weight. Environmental concerns mean that most documents - literature or otherwise - are held in electronic format, with hard copies stored in the Terra Global Library for posterity. Most actual books are considered antiques, though the immense printing boom of the 20th century means that they are not entirely rare - simply considered outmoded. The Amazon Kindle of 2009 and its descendents have progressed to the point where it can hold thousands of books easily and is a popular choice.
Music: Tends to be as varied as it always was, though the unification of Terra has given rise to a number of fusion bands that blend cultural elements. While there are certainly still hold outs in various genres, it's far more common to see a mixing of musical genres nowadays.