Well i've still got a crapload to do in the game, I have a whole pile of side and main quests to do, so I'm no where near finished, however I was desperate to see what happens next, so I did Assassin dood and Garrus’s loyalty quests last night, mined a load of elements, upgraded everything I could afford, saved my game (so I could go back to it and finish it all off later), and went through the relay…
Huge Terminator Reaper

Soon as it said there was a big central chamber and that they were melting down humans I was like… SOOOO going to be building a Reaper, at first I thought they might be rebuilding Sovereign, but then I saw the Human Reaper, very cool
Also interesting that the ‘Harbinger’ is actually a Reaper, inside a Collector General, inside a Drone… and when the base is gonna blow it returns to its Reaper body, very interesting.
So I sent Tali in the vents, Garrus as squad leader, Jacob to help the crew back, Samara for the shield, and Garrus for the Distraction team.
Worked a treat, only lost Jack (which I couldn’t give two hoots about, as she's my least fave character, and I had skipped her loyalty quest anyway so not a big surprise).
I decided to keep the base, so blasted it with radiation.
And, whoa, how many Reapers on the way! Can't wait to see how they are gonna stop that lot! Roll on ME3!
Though, I have to say while ME2 has much improved many things (graphics, combat, level design, inventory etc), I still prefer the storyline of the first game, and I would have to say the ending to ME is even more epic than ME2’s.
ME2 was severely lacking a 'big bad', the collectors just weren't in it enough or had enough interaction with Shepard to be classed as anything other than a 'pesky annoyance'. The game seriously needed a 'Saren' character. The ME2 storyline defiantly suffered from 'middle of a trilogy' syndrome, there was lots of stuff happening, just non of it really moved the plot-line along, it was all just preparation, hardly any 'reveal' at all.
Also I was VERY disappointed at the lack of double-crossing. From the start when EDI said she had locked data banks to be used a 'specific time', and the fact that Cerberus rebuilt your body and could have implanted any number of control/explosive whatever devices into your cybernetics, plus the Illusive Man is forever setting people up, I was 100% certain at some point the poo was going to hit the fan and he was going to take control of the ship, or force you to do something, but then nothing happened... missed opportunity there methinks.
I am by no means done with the game, or unhappy with it, its an excellent game, I just feel it could have been much more, had they fleshed out the Collectors a bit more to make them into a proper enemy you wanted to be victorious over. Not to mention the serious lack of anything to do with the Council or the repercussions of Saren/Sovereign's attack other than the Citadel having a bit of a repair work done.
Anywho, I'll be going back to my old save to finish all the stuff i've not done yet so I can have my 'cannon' save ready for ME3.