Do sitewide links (or blogrolls) carry more weight as compared to just homepage links or links from a single page ? or are the sitewide’s just ignored by search engines and just give you same benefit as a single homepage link?
It depends if you are interested in simply getting hits on your home page, or in quality interaction from potential customers leading to business.
If all you want to do is to drive up the number of hits on your home page then yes, encouraging links to your home page will help you to achieve that.
If you want people to read content on any other pages or to buy anything from your site, you need deep links. Remember that the average surfer has an attention span measure in milliseconds. If they are following a link - whether it’s from a search engine or another website - that they think is going to take them to the nice, juicy content they’re after it, and it instead dumps them unceremoniously at the home page, what do you think they are going to do next?
A small proportion will start to read the site, work out the navigation and explore the site to find what they were looking for. A larger proportion will skim half-way down the home page, click on three or four links at random and then give up. A similar proportion won’t even do that much - they will just go back and try a different site.
Deep links are much better at getting targeted traffic to the right pages on your site.
The corollary to this is that you need to be responsible about ensuring that your old URLs continue to work, and that you put redirects in any time you move or rename a page, so that all those deep links stay alive.
You just need to have a diverse back link profile, all of your links should not be site wide or vice versa …
It comes down to quality over quantity…
You will get PR attribution to each of those links on every page, but they will be reduced in value as they normally are part of the boilerplate and are not contextually positioned inside relevant content.
A link from a relevant page is worth far more than one that is from that site’s home page since the home page of some other site is likely to be far less relevant to a specific page on your site than specific content pages are.
well i think homepage links are better than sidewide links because 1 link from each site is better than bulk links from each site 
Interesting question, and I’d love to hear from others regarding this.
From my experience, sitewide links are not ignored, and each one adds to the PageRank of the referred site. However, I would think Google & co wouldn’t allow this to go beyond a specific point.
Search engines evaluate each web page completely separately so as far as they are concerned there’s no such thing as a home page - just pages.