Solo mining requirement to win a block everyday? What's the hash power requirements to solo mine and win at least one block a day?

Two cases (with 10% luck, means mining requires to iterate 90% of unsuccessful hashes), 


Mine 24 hours a day and win at least one block
Mine 10 - 30 mins and win at least one block
You can mine 1 block roughly every 10 mins, hence total blocks per day is 6 x 24 = 144

The current Hash Rate in the Network is about 70000 GH/sec (Source: Blockchain.info]1

If you have 100% of the Hash power, you will get all the blocks each day.

To get at least one block a day, you will need roughly 0.7% of the current total hash power (1/144), that is about 486 GH/sec of hash power.

To get at least one coin a day, you will need at least 19.44GH/sec of hash power ( 486 / 25 coins per block)

The hash power requirement will change as the network hash rate rises with more ASIC devices shipped.