Up's defintely a fantastic album, and if it ends up being the one that caps his career it'll be a fine way to end it.
A top 10 is all-but impossible for me, the best I can do is 15. In chronological order (* indicates top 5):
1. Moribund the Burgermeister
2. Humdrum (*)
3. Here Comes The Flood
4. On The Air (live version on Plays Live is fanastic too)
5. DIY (as above)
6. Home Sweet Home
7. The Rhythm of the Heat
8. San Jacinto (*)
9. Lay Your Hands On Me (*)
10. Red Rain
11. Mercy Street (*)
12. In Your Eyes
13.Secret World (* - live version on Secret World Live may be his single finest moment)
14. I Grieve
15. Signal To Noise
And even that kills me to leave off songs like White Shadow, Mother of Violence, Family Snapshot, Not One Of Us, No Self Control, Intruder, Biko, Wallflower, Love to be Loved, Digging In The Dirt, Downside-Up, Father Son, Make Tomorrow, Darkness, Sky Blue, My Head Sounds Like That...
PG 2 (Scratch) seems to be the runt of the litter with most fans but I absolutely love it. It has a really cool 'low-fi' feel that I like, especially coming after the 'everything but the kitchen sink' approach he took on his debut, where it seems to me he was eager to explore all the music he hadn't been able to in Genesis (barbershop quartet, jazz, orchestral), with...'interesting' results, if a little bit messy. The debut sprawls, it's like a huge feast, whereas PG2 feels like some cool little record he recorded in his basement during a quiet moment.