What benefits do you gain from playing the Guild Wars 2 beta

Actual characters cannot be transferred to GW2, though you will be able to reserve character names. If you purchase Guild Wars: Eye of the North, you will have access to the Hall of Monuments. The HoM is a way to track various achievements from GW1, such as miniatures collected, prestige armor/weapons acquired, titles and accomplishments you've achieved, etc. ArenaNet has confirmed that your character in GW2 will benefit from any accomplishments you have logged with the Hall of Monument by linking your two accounts. The bonuses you can acquire are account-based, not character-based, so if GW1 character A got the Tyrian Explorer title and GW1 character B got the Canthan Explorer title, you will still get the benefit from both characters' accomplishments in GW2 as long as you've logged those accomplishments in the HoM. Happy achievement hunting! :)

Additionally, there is now a website where you can fill in your character's name and your GW2 rewards will be calculated based on what is currently in the Hall of Monuments. Calculations are based on account, so even if you fill in a certain character's name, the rewards you are receiving are based on your account as a whole. You will be able to continue adding to the HoM after GW2 releases.

Additional Source

I am not entire sure what you are asking about in your question, but here is a list of stuff that may fall under what you are interested in:

1. Challenge and Elite (none storyline missions/quests) - Fissure of Woe, Underworld, Sorrow's Furnace, Tomb of Primeval Kings, The Deep, Urgoz's Warren, Mallyx. These are are all elite missions/zones that grant unique greens, possibly minis, and other rewards is not related to the storyline.

2. The series of War in Kryta quests that were added in over the previous year or so which leads up to Guild Wars 2 are probably the latest in terms of story (and possibly the final story related missions).

3. The Vision of Glint quest series can be done after the prophecies missions.

4. The final quests for each campaign are: Hell's Precipice (prophecies), Imperial Sanctum (factions), and Abbadon's Gate.

5. The Eye of the North update has a direct link to events in GW2. The final mission for EotN is A Time for Heroes.

6. Filling up your Hall of Monuments or maxing all titles (very challenging and impossible for certain discontinued titles) may be considered the final quest for some.

Updated as of 8/18/2011

7. hard mode quests that you can complete.

8. Winds of change, which is the Canthan equivalent of events and stories leading up to Guild Wars 2.