First of, if this kinda threads irritate you, please do not read any further 
I currently have a late 2008 15" MBP. With 8gb of ram and SSD it is still running fast enough for me, but not for long... Only program I've started to have trouble running is Final Cut Pro X, which is a shame cause the first versions of it ran fine, but now it's started to lag (even with the lightest settings.) Luckily for me, I use it very seldomly.
Reasons I'm planning on skipping Haswell and aim for Broadwell:
-Hopefully SSD prices will have gone down a bit by then and possibly there would be a 1TB SSD alternative. (Currently having two hard drives in my MBP, which easily and cheaply give me over 1TB of HD space. I need this for Aperture and iTunes libraries. Unfortunately using external HDs for those is not very handy, at least with iTunes I had the problem that it would at times forget that my library folder is on an external hd and instead start putting new songs on the main HD -> SUPER annoying. I would assume Aperture would do the same. Not worth the trouble to use external HDs for these libraries.)
-Thunderbolt 2 will be released in the beginning of 2014. I currently do not have a thunderbolt connection in anything yet, and have not missed it. I would rather just get a thunderbolt 2 laptop straight away if possible. Though I'm sure I would not be able to afford any thunderbolt compatible devices for ages, but I plan to use my laptop for like 5 years. Hopefully by then there will be some decently priced thunderbolt (2) compatible devices... Maybe even an external GPU?
-Broadwell should use even less battery
-Broadwell will bring SATA Express support, which would be cool, but not really a real reason to skip haswell
-Overall retina displays (and thus rMBPs) would probably be more affordable
Some things that might already arrive with Haswell, but possibly not:
-And I would hope that the brightest setting on the rMBP would be brighter. I dont care if it would use more battery, but currently the brightest setting on a sunny day is just a bit too dim for me.
-HDMI out port with decent 4K support (meaning: supports more than 30 frames per sec, would allow to use a 4K tv as a desktop monitor. Can currently be done with HDMI 1.4, but 30 hertz is quite low for anything else except movies/tv.)
-USB 3.0 with 10gbps
And yes! If I wasn't a poor student, I would already very likely buy a haswell MBP
I currently have a late 2008 15" MBP. With 8gb of ram and SSD it is still running fast enough for me, but not for long... Only program I've started to have trouble running is Final Cut Pro X, which is a shame cause the first versions of it ran fine, but now it's started to lag (even with the lightest settings.) Luckily for me, I use it very seldomly.
Reasons I'm planning on skipping Haswell and aim for Broadwell:
-Hopefully SSD prices will have gone down a bit by then and possibly there would be a 1TB SSD alternative. (Currently having two hard drives in my MBP, which easily and cheaply give me over 1TB of HD space. I need this for Aperture and iTunes libraries. Unfortunately using external HDs for those is not very handy, at least with iTunes I had the problem that it would at times forget that my library folder is on an external hd and instead start putting new songs on the main HD -> SUPER annoying. I would assume Aperture would do the same. Not worth the trouble to use external HDs for these libraries.)
-Thunderbolt 2 will be released in the beginning of 2014. I currently do not have a thunderbolt connection in anything yet, and have not missed it. I would rather just get a thunderbolt 2 laptop straight away if possible. Though I'm sure I would not be able to afford any thunderbolt compatible devices for ages, but I plan to use my laptop for like 5 years. Hopefully by then there will be some decently priced thunderbolt (2) compatible devices... Maybe even an external GPU?
-Broadwell should use even less battery
-Broadwell will bring SATA Express support, which would be cool, but not really a real reason to skip haswell
-Overall retina displays (and thus rMBPs) would probably be more affordable
Some things that might already arrive with Haswell, but possibly not:
-And I would hope that the brightest setting on the rMBP would be brighter. I dont care if it would use more battery, but currently the brightest setting on a sunny day is just a bit too dim for me.
-HDMI out port with decent 4K support (meaning: supports more than 30 frames per sec, would allow to use a 4K tv as a desktop monitor. Can currently be done with HDMI 1.4, but 30 hertz is quite low for anything else except movies/tv.)
-USB 3.0 with 10gbps
And yes! If I wasn't a poor student, I would already very likely buy a haswell MBP