Are you any good with microprocessors? This is an ideal project for a PIC microcontroller. If you are going to progress your electronics career, I strongly suggest you have a play with them - they will really make your expertese much better. I would avoid using discrete logic blocks.
You also need to look at Real Time Clocks (RTCs). these cute little chips have a 32Khz oscillator connected to them and increment seconds, days, months, years, day of week etc and take a whole ton of grief away from clock designing.
As for the 7 segment display, take a look at the MAX7219. this drives 7 segment displays.
But you really need to start with a micro at the heart of the design and you can learn PICs in a matter of days - and there is a whole ton of software on the net to get your started!