Re: "Clean" my partitions after removing Windows and Leopard
This is actually not too bad (have seen much worse).
Do NOT delete sda7. This is likely where you have installed Kubuntu itself.
What do you wish to do? Clean things up without reinstalling Kubuntu? If so, then it is just a matter of deleting sda1 and sda6, reinstalling your bootloader and using the freed-up space however you like. You could make new ext4 partitions, move your data to one of the new partitions and then reformat sda5 to ext4 as well for better performance and journalling (better data safety, more efficient use of disk space--fat32 is awful for security, redundancy or efficiency).
If you prefer to have a really neat and tidy partition scheme, with / at the front of the disk, /home next, and a data partition for permanent data that survives across different OSes and installs, then you can either try moving partitions (which is always riskier) or you could use this opportunity to reinstall Kubuntu.
The single biggest cause of lost data, frantic pleas for help and disappointment on these forums is due to borked partitioning.
All partitioning has to be done from a LiveDVD/USB. Your HDD cannot be mounted while you fiddle around with its partition table.
Newb: How far must I jump to clear the ledge halfway down?
Guru: It's bad to jump off cliffs. Let's look at better options.
Newb: Stop harping about "best practices" and just tell me.