If you have a working internet connection best place is the repository. A well set up repository can let you access lots of softwares.
Here's mine /etc/apt/sources.list
Code:
deb *archive.ubuntu.com/ubuntu dapper main restricted universe multiverse
deb-src *archive.ubuntu.com/ubuntu dapper main restricted universe multiverse
deb *archive.ubuntu.com/ubuntu dapper-updates main restricted universe multiverse
deb-src *archive.ubuntu.com/ubuntu dapper-updates main restricted universe multiverse
deb *archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse
deb-src *archive.ubuntu.com/ubuntu dapper-backports main restricted universe multiverse
deb *security.ubuntu.com/ubuntu dapper-security main restricted universe multiverse
deb-src *security.ubuntu.com/ubuntu dapper-security main restricted universe multiverse
deb *packages.freecontrib.org/ubuntu/plf dapper free non-free
deb-src *packages.freecontrib.org/ubuntu/plf dapper free non-free
deb *archive.canonical.com/ubuntu dapper-commercial main
deb *wine.sourceforge.net/apt/ binary/
deb *wine.budgetdedicated.com/apt dapper main
deb *deb.opera.com/opera/ etch non-free
deb *kubuntu.org/packages/kde-latest dapper main
deb-src *kubuntu.org/packages/kde-latest dapper main
deb *kubuntu.org/packages/koffice-latest dapper main
deb *kubuntu.org/packages/amarok-latest dapper main
deb *compiztools.free.fr/debian unstable main
deb *www.beerorkid.com/compiz/ dapper main
deb ftp://cipherfunk.org/pub/packages/ubuntu/ dapper main
deb-src ftp://cipherfunk.org/pub/packages/ubuntu dapper main
deb *nightlies.videolan.org/build/dapper-i386 /
deb *download.skype.com/linux/repos/debian/ stable non-free
So, you can manually download deb files from these sites manually too. But, then it will be difficult to manage the dependancies.
Also, some packages in my repositories are betas, I would advise you not to install them for now.