Depends what you do with it.... I have 25 years if Drawings, Specifications and business records and it takes up a merer 100 GB.
A single game can take up 40 GB and large music, movie libraries will eat up GB fast.
Our laptops are used for preparing Field Drawings in AutoCAD and the 7200 rpm 750 GB SSHDs serve us extremely well in that department. If you pick a laptop that lets you pick your components, you may find very little difference in cost for various HD sizes.
For example.... the following comes standard w/ a 1TB drive and offers various alternatives for upgrades at the costs listed
http://www.lpc-digital.com/sager-np7339-features.html
1 TB HGST Travelstar™ 7K1000 7200 RPM SATA 6Gb/s Hard Drive - Special! $0.00
Crucial® BX100 120GB SATA 6Gb/s SSD $20.00
120GB Samsung® 850 EVO Series SATA3 Solid State Drive $25.00
1TB Seagate Solid State Hybrid 8GB ST1000LM014 64MB Cache SATA 6.0Gb/s $60.00
Crucial® BX100 250GB SATA 6Gb/s SSD $65.00
2TB 5400 RPM SATA 3.0Gb/s Hard Drive $85.00
250GB Samsung® 850 EVO Series SATA3 Solid State Drive $85.00
Samsung® 256GB 850 Pro Series SSD with 3D V-NAND Architecture $120.00
Intel® 730 Series 240GB Solid State Drive SATA 6Gb/s $145.00
Crucial® BX100 500GB SATA 6Gb/s SSD $170.00
500GB Samsung® 850 EVO Series SATA3 Solid State Drive $190.00
Intel® 730 Series 480GB Solid State Drive SATA 6Gb/s $285.00
1TB Samsung 850 EVO Series SATA3 Solid State Drive $365.00
Crucial® BX100 1TB SATA 6Gb/s SSD $370.00
1TB Samsung® 850 Pro Series SATA3 Solid State Disk Drive $475.00